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Hord JM, Anderson ME, Prouty SJ, Melton S, Gastel Z, Zimmerman K, Weiss RM, Campbell KP. Matriglycan maintains t-tubule structural integrity in cardiac muscle. Proc Natl Acad Sci U S A 2024; 121:e2402890121. [PMID: 38771868 DOI: 10.1073/pnas.2402890121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/08/2024] [Indexed: 05/23/2024] Open
Abstract
Maintaining the structure of cardiac membranes and membrane organelles is essential for heart function. A critical cardiac membrane organelle is the transverse tubule system (called the t-tubule system) which is an invagination of the surface membrane. A unique structural characteristic of the cardiac muscle t-tubule system is the extension of the extracellular matrix (ECM) from the surface membrane into the t-tubule lumen. However, the importance of the ECM extending into the cardiac t-tubule lumen is not well understood. Dystroglycan (DG) is an ECM receptor in the surface membrane of many cells, and it is also expressed in t-tubules in cardiac muscle. Extensive posttranslational processing and O-glycosylation are required for DG to bind ECM proteins and the binding is mediated by a glycan structure known as matriglycan. Genetic disruption resulting in defective O-glycosylation of DG results in muscular dystrophy with cardiorespiratory pathophysiology. Here, we show that DG is essential for maintaining cardiac t-tubule structural integrity. Mice with defects in O-glycosylation of DG developed normal t-tubules but were susceptible to stress-induced t-tubule loss or severing that contributed to cardiac dysfunction and disease progression. Finally, we observed similar stress-induced cardiac t-tubule disruption in a cohort of mice that solely lacked matriglycan. Collectively, our data indicate that DG in t-tubules anchors the luminal ECM to the t-tubule membrane via the polysaccharide matriglycan, which is critical to transmitting structural strength of the ECM to the t-tubules and provides resistance to mechanical stress, ultimately preventing disruptions in cardiac t-tubule integrity.
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Affiliation(s)
- Jeffrey M Hord
- HHMI, University of Iowa, Iowa City, IA 52242
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Iowa, Iowa City, IA 52242
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242
- Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Mary E Anderson
- HHMI, University of Iowa, Iowa City, IA 52242
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Iowa, Iowa City, IA 52242
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242
- Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Sally J Prouty
- HHMI, University of Iowa, Iowa City, IA 52242
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Iowa, Iowa City, IA 52242
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242
- Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Shelly Melton
- HHMI, University of Iowa, Iowa City, IA 52242
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Iowa, Iowa City, IA 52242
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242
- Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Zeita Gastel
- HHMI, University of Iowa, Iowa City, IA 52242
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Iowa, Iowa City, IA 52242
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242
- Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Kathy Zimmerman
- Division of Cardiology, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Robert M Weiss
- Division of Cardiology, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
- Abboud Cardiovascular Research Center, Carver College of Medicine, Department of Internal Medicine-Cardiovascular Medicine, University of Iowa, Iowa City, IA 52242
- Iowa City Veterans Affairs Health Care System, University of Iowa, Iowa City, IA 52242
| | - Kevin P Campbell
- HHMI, University of Iowa, Iowa City, IA 52242
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Iowa, Iowa City, IA 52242
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242
- Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242
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Eliezeck M, Guedes Jesus IC, Scalzo SA, Sanches BDL, Silva KSC, Costa M, Mesquita T, Rocha-Resende C, Szawka RE, Guatimosim S. β-Adrenergic signaling drives structural and functional maturation of mouse cardiomyocytes. Am J Physiol Cell Physiol 2024; 326:C1334-C1344. [PMID: 38557356 DOI: 10.1152/ajpcell.00426.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 02/28/2024] [Accepted: 03/14/2024] [Indexed: 04/04/2024]
Abstract
Cardiac maturation represents the last phase of heart development and is characterized by morphofunctional alterations that optimize the heart for efficient pumping. Its understanding provides important insights into cardiac regeneration therapies. Recent evidence implies that adrenergic signals are involved in the regulation of cardiac maturation, but the mechanistic underpinnings involved in this process are poorly understood. Herein, we explored the role of β-adrenergic receptor (β-AR) activation in determining structural and functional components of cardiomyocyte maturation. Temporal characterization of tyrosine hydroxylase and norepinephrine levels in the mouse heart revealed that sympathetic innervation develops during the first 3 wk of life, concurrent with the rise in β-AR expression. To assess the impact of adrenergic inhibition on maturation, we treated mice with propranolol, isolated cardiomyocytes, and evaluated morphofunctional parameters. Propranolol treatment reduced heart weight, cardiomyocyte size, and cellular shortening, while it increased the pool of mononucleated myocytes, resulting in impaired maturation. No changes in t-tubules were observed in cells from propranolol mice. To establish a causal link between β-AR signaling and cardiomyocyte maturation, mice were subjected to sympathectomy, followed or not by restoration with isoproterenol treatment. Cardiomyocytes from sympathectomyzed mice recapitulated the salient immaturity features of propranolol-treated mice, with the additional loss of t-tubules. Isoproterenol rescued the maturation deficits induced by sympathectomy, except for the t-tubule alterations. Our study identifies the β-AR stimuli as a maturation promoting signal and implies that this pathway can be modulated to improve cardiac regeneration therapies.NEW & NOTEWORTHY Maturation involves a series of morphofunctional alterations vital to heart development. Its regulatory mechanisms are only now being unveiled. Evidence implies that adrenergic signaling regulates cardiac maturation, but the mechanisms are poorly understood. To address this point, we blocked β-ARs or performed sympathectomy followed by rescue experiments with isoproterenol in neonatal mice. Our study identifies the β-AR stimuli as a maturation signal for cardiomyocytes and highlights the importance of this pathway in cardiac regeneration therapies.
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Affiliation(s)
- Marcos Eliezeck
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Itamar Couto Guedes Jesus
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Sérgio A Scalzo
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Bruno de Lima Sanches
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Kaoma Stephani Costa Silva
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Mateus Costa
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Thássio Mesquita
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States
| | - Cibele Rocha-Resende
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Raphael E Szawka
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Silvia Guatimosim
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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Xu C, Zhang G, Wang X, Huang X, Zhang J, Han S, Wang J, Hall DD, Xu R, He F, Chang X, Wang F, Xie W, Wu Z, Song LS, Han P. Ptpn23 Controls Cardiac T-Tubule Patterning by Promoting the Assembly of Dystrophin-Glycoprotein Complex. Circulation 2024; 149:1375-1390. [PMID: 38214189 PMCID: PMC11039371 DOI: 10.1161/circulationaha.123.065767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 12/14/2023] [Indexed: 01/13/2024]
Abstract
BACKGROUND Cardiac transverse tubules (T-tubules) are anchored to sarcomeric Z-discs by costameres to establish a regular spaced pattern. One of the major components of costameres is the dystrophin-glycoprotein complex (DGC). Nevertheless, how the assembly of the DGC coordinates with the formation and maintenance of T-tubules under physiological and pathological conditions remains unclear. METHODS Given the known role of Ptpn23 (protein tyrosine phosphatase, nonreceptor type 23) in regulating membrane deformation, its expression in patients with dilated cardiomyopathy was determined. Taking advantage of Cre/Loxp, CRISPR/Cas9, and adeno-associated virus 9 (AAV9)-mediated in vivo gene editing, we generated cardiomyocyte-specific Ptpn23 and Actn2 (α-actinin-2, a major component of Z-discs) knockout mice. We also perturbed the DGC by using dystrophin global knockout mice (DmdE4*). MM 4-64 and Di-8-ANEPPS staining, Cav3 immunofluorescence, and transmission electron microscopy were performed to determine T-tubule structure in isolated cells and intact hearts. In addition, the assembly of the DGC with Ptpn23 and dystrophin loss of function was determined by glycerol-gradient fractionation and SDS-PAGE analysis. RESULTS The expression level of Ptpn23 was reduced in failing hearts from dilated cardiomyopathy patients and mice. Genetic deletion of Ptpn23 resulted in disorganized T-tubules with enlarged diameters and progressive dilated cardiomyopathy without affecting sarcomere organization. AAV9-mediated mosaic somatic mutagenesis further indicated a cell-autonomous role of Ptpn23 in regulating T-tubule formation. Genetic and biochemical analyses showed that Ptpn23 was essential for the integrity of costameres, which anchor the T-tubule membrane to Z-discs, through interactions with α-actinin and dystrophin. Deletion of α-actinin altered the subcellular localization of Ptpn23 and DGCs. In addition, genetic inactivation of dystrophin caused similar T-tubule defects to Ptpn23 loss-of-function without affecting Ptpn23 localization at Z-discs. Last, inducible Ptpn23 knockout at 1 month of age showed Ptpn23 is also required for the maintenance of T-tubules in adult cardiomyocytes. CONCLUSIONS Ptpn23 is essential for cardiac T-tubule formation and maintenance along Z-discs. During postnatal heart development, Ptpn23 interacts with sarcomeric α-actinin and coordinates the assembly of the DGC at costameres to sculpt T-tubule spatial patterning and morphology.
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Affiliation(s)
- Chen Xu
- Center for Genetic Medicine, The Fourth Affiliated Hospital (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.), Zhejiang University School of Medicine, Hangzhou, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
- Zhejiang Provincial Key Laboratory of Genetic & Developmental Disorders, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
| | - Ge Zhang
- Center for Genetic Medicine, The Fourth Affiliated Hospital (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.), Zhejiang University School of Medicine, Hangzhou, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
- Zhejiang Provincial Key Laboratory of Genetic & Developmental Disorders, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
| | - Xinjian Wang
- Center for Genetic Medicine, The Fourth Affiliated Hospital (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.), Zhejiang University School of Medicine, Hangzhou, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
- Zhejiang Provincial Key Laboratory of Genetic & Developmental Disorders, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
| | - Xiaozhi Huang
- Center for Genetic Medicine, The Fourth Affiliated Hospital (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.), Zhejiang University School of Medicine, Hangzhou, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
- Zhejiang Provincial Key Laboratory of Genetic & Developmental Disorders, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
| | - Jiayin Zhang
- Center for Genetic Medicine, The Fourth Affiliated Hospital (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.), Zhejiang University School of Medicine, Hangzhou, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
- Zhejiang Provincial Key Laboratory of Genetic & Developmental Disorders, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
| | - Shuxian Han
- Center for Genetic Medicine, The Fourth Affiliated Hospital (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.), Zhejiang University School of Medicine, Hangzhou, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
- Zhejiang Provincial Key Laboratory of Genetic & Developmental Disorders, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
| | - Jinxi Wang
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City (J.W., D.D.H., L.-S.S.)
| | - Duane D Hall
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City (J.W., D.D.H., L.-S.S.)
| | - Ruoqing Xu
- Center for Genetic Medicine, The Fourth Affiliated Hospital (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.), Zhejiang University School of Medicine, Hangzhou, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
- Zhejiang Provincial Key Laboratory of Genetic & Developmental Disorders, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
| | - Feng He
- Center for Genetic Medicine, The Fourth Affiliated Hospital (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.), Zhejiang University School of Medicine, Hangzhou, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
- Zhejiang Provincial Key Laboratory of Genetic & Developmental Disorders, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
| | - Xing Chang
- Research Center for Industries of the Future, Westlake University, Hangzhou, China (X.C.)
| | - Fudi Wang
- School of Public Health, State Key Laboratory of Experimental Hematology (F.W.), Zhejiang University School of Medicine, Hangzhou, China
| | - Wenjun Xie
- Department of Cardiology, First Affiliated Hospital of Xi'an Jiaotong University, China (W.X.)
| | - Zhichao Wu
- Department of Thoracic Surgery, People's Hospital of Xinjiang Uyghur Autonomous Region, Urumqi, China (Z.W.)
- Department of Cardiovascular Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China (Z.W.)
| | - Long-Sheng Song
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City (J.W., D.D.H., L.-S.S.)
| | - Peidong Han
- Center for Genetic Medicine, The Fourth Affiliated Hospital (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.), Zhejiang University School of Medicine, Hangzhou, China
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
- Zhejiang Provincial Key Laboratory of Genetic & Developmental Disorders, Hangzhou, China (C.X., G.Z., X.W., X.H., J.Z., S.H., R.X., F.H., P.H.)
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Giraud Q, Laporte J. Amphiphysin-2 (BIN1) functions and defects in cardiac and skeletal muscle. Trends Mol Med 2024:S1471-4914(24)00030-3. [PMID: 38514365 DOI: 10.1016/j.molmed.2024.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/11/2024] [Accepted: 02/14/2024] [Indexed: 03/23/2024]
Abstract
Amphiphysin-2 is a ubiquitously expressed protein also known as bridging integrator 1 (BIN1), playing a critical role in membrane remodeling, trafficking, and cytoskeleton dynamics in a wide range of tissues. Mutations in the gene encoding BIN1 cause centronuclear myopathies (CNM), and recent evidence has implicated BIN1 in heart failure, underlining its crucial role in both skeletal and cardiac muscle. Furthermore, altered expression of BIN1 is linked to an increased risk of late-onset Alzheimer's disease and several types of cancer, including breast, colon, prostate, and lung cancers. Recently, the first proof-of-concept for potential therapeutic strategies modulating BIN1 were obtained for muscle diseases. In this review article, we discuss the similarities and differences in BIN1's functions in cardiac and skeletal muscle, along with its associated diseases and potential therapies.
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Affiliation(s)
- Quentin Giraud
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC, INSERM U1258, CNRS UMR7104, Université de Strasbourg, Illkirch-Graffenstaden, 67400, France
| | - Jocelyn Laporte
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC, INSERM U1258, CNRS UMR7104, Université de Strasbourg, Illkirch-Graffenstaden, 67400, France.
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Hall DD, Takeshima H, Song LS. Structure, Function, and Regulation of the Junctophilin Family. Annu Rev Physiol 2024; 86:123-147. [PMID: 37931168 PMCID: PMC10922073 DOI: 10.1146/annurev-physiol-042022-014926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
In both excitable and nonexcitable cells, diverse physiological processes are linked to different calcium microdomains within nanoscale junctions that form between the plasma membrane and endo-sarcoplasmic reticula. It is now appreciated that the junctophilin protein family is responsible for establishing, maintaining, and modulating the structure and function of these junctions. We review foundational findings from more than two decades of research that have uncovered how junctophilin-organized ultrastructural domains regulate evolutionarily conserved biological processes. We discuss what is known about the junctophilin family of proteins. Our goal is to summarize the current knowledge of junctophilin domain structure, function, and regulation and to highlight emerging avenues of research that help our understanding of the transcriptional, translational, and post-translational regulation of this gene family and its roles in health and during disease.
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Affiliation(s)
- Duane D Hall
- Department of Internal Medicine, Division of Cardiovascular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA; ,
| | - Hiroshi Takeshima
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Long-Sheng Song
- Department of Internal Medicine, Division of Cardiovascular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA; ,
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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Moammer H, Bai J, Jones TLM, Ward M, Barrett C, Crossman DJ. Pirfenidone increases transverse tubule length in the infarcted rat myocardium. Interface Focus 2023; 13:20230047. [PMID: 38106917 PMCID: PMC10722216 DOI: 10.1098/rsfs.2023.0047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/10/2023] [Indexed: 12/19/2023] Open
Abstract
Transverse (t)-tubule remodelling is a prominent feature of heart failure with reduced ejection fraction (HFrEF). In our previous research, we identified an increased amount of collagen within the t-tubules of HFrEF patients, suggesting fibrosis could contribute to the remodelling of t-tubules. In this research, we tested this hypothesis in a rodent model of myocardial infarction induced heart failure that was treated with the anti-fibrotic pirfenidone. Confocal microscopy demonstrated loss of t-tubules within the border zone region of the infarct. This was documented as a reduction in t-tubule frequency, area, length, and transverse elements. Eight weeks of pirfenidone treatment was able to significantly increase the area and length of the t-tubules within the border zone. Echocardiography showed no improvement with pirfenidone treatment. Surprisingly, pirfenidone significantly increased the thickness of the t-tubules in the remote left ventricle of heart failure animals. Dilation of t-tubules is a common feature in heart failure suggesting this may negatively impact function but there was no functional loss associated with pirfenidone treatment. However, due to the relatively short duration of treatment compared to that used clinically, the impact of long-term treatment on t-tubule structure should be investigated in future studies.
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Affiliation(s)
- Hussam Moammer
- Manaaki Manawa—The Centre for Heart Research, Department of Physiology, School of Medical and Health Sciences, Faculty of Medical and Health Sciences, Waipapa Taumata Rau / The University of Auckland, Park Road, Grafton, Auckland, New Zealand
- Department of Clinical Physiology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Jizhong Bai
- Manaaki Manawa—The Centre for Heart Research, Department of Physiology, School of Medical and Health Sciences, Faculty of Medical and Health Sciences, Waipapa Taumata Rau / The University of Auckland, Park Road, Grafton, Auckland, New Zealand
| | - Timothy L. M. Jones
- Manaaki Manawa—The Centre for Heart Research, Department of Physiology, School of Medical and Health Sciences, Faculty of Medical and Health Sciences, Waipapa Taumata Rau / The University of Auckland, Park Road, Grafton, Auckland, New Zealand
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Marie Ward
- Manaaki Manawa—The Centre for Heart Research, Department of Physiology, School of Medical and Health Sciences, Faculty of Medical and Health Sciences, Waipapa Taumata Rau / The University of Auckland, Park Road, Grafton, Auckland, New Zealand
| | - Caroyln Barrett
- Manaaki Manawa—The Centre for Heart Research, Department of Physiology, School of Medical and Health Sciences, Faculty of Medical and Health Sciences, Waipapa Taumata Rau / The University of Auckland, Park Road, Grafton, Auckland, New Zealand
| | - David J. Crossman
- Manaaki Manawa—The Centre for Heart Research, Department of Physiology, School of Medical and Health Sciences, Faculty of Medical and Health Sciences, Waipapa Taumata Rau / The University of Auckland, Park Road, Grafton, Auckland, New Zealand
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Chakraborty P, Aggarwal AK, Nair MKK, Massé S, Riazi S, Nanthakumar K. Restoration of calcium release synchrony: A novel target for heart failure and ventricular arrhythmia. Heart Rhythm 2023; 20:1773-1781. [PMID: 37678492 DOI: 10.1016/j.hrthm.2023.08.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/13/2023] [Accepted: 08/31/2023] [Indexed: 09/09/2023]
Abstract
Myocardial calcium (Ca2+) signaling plays a crucial role in contractile function and membrane electrophysiology. An abnormal myocardial Ca2+ transient is linked to heart failure and ventricular arrhythmias. At the subcellular level, the synchronous release of Ca2+ sparks from sarcoplasmic Ca2+ release units determines the configuration and amplitude of the global Ca2+ transient. This narrative review evaluates the role of aberrant Ca2+ release synchrony in the pathophysiology of cardiomyopathies and ventricular arrhythmias. The potential therapeutic benefits of restoration of Ca2+ release synchrony in heart failure and ventricular arrhythmias are also discussed.
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Affiliation(s)
- Praloy Chakraborty
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada; Heart Rhythm Institute, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma
| | - Arjun K Aggarwal
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Madhav Krishna Kumar Nair
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Stéphane Massé
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Sheila Riazi
- Malignant Hyperthermia Investigation Unit, Department of Anesthesia and Pain Management, University Health Network, Toronto, Ontario, Canada
| | - Kumaraswamy Nanthakumar
- The Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.
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Waddell HMM, Mereacre V, Alvarado FJ, Munro ML. Clustering properties of the cardiac ryanodine receptor in health and heart failure. J Mol Cell Cardiol 2023; 185:38-49. [PMID: 37890552 PMCID: PMC10717225 DOI: 10.1016/j.yjmcc.2023.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 10/09/2023] [Accepted: 10/24/2023] [Indexed: 10/29/2023]
Abstract
The cardiac ryanodine receptor (RyR2) is an intracellular Ca2+ release channel vital for the function of the heart. Physiologically, RyR2 is triggered to release Ca2+ from the sarcoplasmic reticulum (SR) which enables cardiac contraction; however, spontaneous Ca2+ leak from RyR2 has been implicated in the pathophysiology of heart failure (HF). RyR2 channels have been well documented to assemble into clusters within the SR membrane, with the organisation of RyR2 clusters recently gaining interest as a mechanism by which the occurrence of pathological Ca2+ leak is regulated, including in HF. In this review, we explain the terminology relating to key nanoscale RyR2 clustering properties as both single clusters and functionally grouped Ca2+ release units, with a focus on the advancements in super-resolution imaging approaches which have enabled the detailed study of cluster organisation. Further, we discuss proposed mechanisms for modulating RyR2 channel organisation and the debate regarding the potential impact of cluster organisation on Ca2+ leak activity. Finally, recent experimental evidence investigating the nanoscale remodelling and functional alterations of RyR2 clusters in HF is discussed with consideration of the clinical implications.
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Affiliation(s)
- Helen M M Waddell
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Valeria Mereacre
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Francisco J Alvarado
- Department of Medicine and Cardiovascular Research Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Michelle L Munro
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
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9
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Kwan Z, Paulose Nadappuram B, Leung MM, Mohagaonkar S, Li A, Amaradasa KS, Chen J, Rothery S, Kibreab I, Fu J, Sanchez-Alonso JL, Mansfield CA, Subramanian H, Kondrashov A, Wright PT, Swiatlowska P, Nikolaev VO, Wojciak-Stothard B, Ivanov AP, Edel JB, Gorelik J. Microtubule-Mediated Regulation of β 2AR Translation and Function in Failing Hearts. Circ Res 2023; 133:944-958. [PMID: 37869877 PMCID: PMC10635332 DOI: 10.1161/circresaha.123.323174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 10/11/2023] [Accepted: 10/11/2023] [Indexed: 10/24/2023]
Abstract
BACKGROUND β1AR (beta-1 adrenergic receptor) and β2AR (beta-2 adrenergic receptor)-mediated cyclic adenosine monophosphate signaling has distinct effects on cardiac function and heart failure progression. However, the mechanism regulating spatial localization and functional compartmentation of cardiac β-ARs remains elusive. Emerging evidence suggests that microtubule-dependent trafficking of mRNP (messenger ribonucleoprotein) and localized protein translation modulates protein compartmentation in cardiomyocytes. We hypothesized that β-AR compartmentation in cardiomyocytes is accomplished by selective trafficking of its mRNAs and localized translation. METHODS The localization pattern of β-AR mRNA was investigated using single molecule fluorescence in situ hybridization and subcellular nanobiopsy in rat cardiomyocytes. The role of microtubule on β-AR mRNA localization was studied using vinblastine, and its effect on receptor localization and function was evaluated with immunofluorescent and high-throughput Förster resonance energy transfer microscopy. An mRNA protein co-detection assay identified plausible β-AR translation sites in cardiomyocytes. The mechanism by which β-AR mRNA is redistributed post-heart failure was elucidated by single molecule fluorescence in situ hybridization, nanobiopsy, and high-throughput Förster resonance energy transfer microscopy on 16 weeks post-myocardial infarction and detubulated cardiomyocytes. RESULTS β1AR and β2AR mRNAs show differential localization in cardiomyocytes, with β1AR found in the perinuclear region and β2AR showing diffuse distribution throughout the cell. Disruption of microtubules induces a shift of β2AR transcripts toward the perinuclear region. The close proximity between β2AR transcripts and translated proteins suggests that the translation process occurs in specialized, precisely defined cellular compartments. Redistribution of β2AR transcripts is microtubule-dependent, as microtubule depolymerization markedly reduces the number of functional receptors on the membrane. In failing hearts, both β1AR and β2AR mRNAs are redistributed toward the cell periphery, similar to what is seen in cardiomyocytes undergoing drug-induced detubulation. This suggests that t-tubule remodeling contributes to β-AR mRNA redistribution and impaired β2AR function in failing hearts. CONCLUSIONS Asymmetrical microtubule-dependent trafficking dictates differential β1AR and β2AR localization in healthy cardiomyocyte microtubules, underlying the distinctive compartmentation of the 2 β-ARs on the plasma membrane. The localization pattern is altered post-myocardial infarction, resulting from transverse tubule remodeling, leading to distorted β2AR-mediated cyclic adenosine monophosphate signaling.
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MESH Headings
- Rats
- Animals
- In Situ Hybridization, Fluorescence
- Heart Failure/metabolism
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Myocardial Infarction/metabolism
- Myocytes, Cardiac/metabolism
- Cyclic AMP/metabolism
- Receptors, Adrenergic, beta-1/metabolism
- Microtubules/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Adenosine Monophosphate/metabolism
- Adenosine Monophosphate/pharmacology
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Affiliation(s)
- Zoe Kwan
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
- Department of Chemistry (Z.K., B.P.N., A.P.I., J.B.E.), Imperial College London, United Kingdom
| | - Binoy Paulose Nadappuram
- Department of Chemistry (Z.K., B.P.N., A.P.I., J.B.E.), Imperial College London, United Kingdom
- Department of Pure and Applied Chemistry, University of Strathclyde, United Kingdom (B.P.N.)
| | - Manton M. Leung
- Sir William Dunn School of Pathology, University of Oxford, United Kingdom (M.M.L.)
| | - Sanika Mohagaonkar
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Ao Li
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Kumuthu S. Amaradasa
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Ji Chen
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Stephen Rothery
- FILM Facility, Imperial College London, United Kingdom (S.R.)
| | - Iyobel Kibreab
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Jiarong Fu
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Jose L. Sanchez-Alonso
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Catherine A. Mansfield
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | | | - Alexander Kondrashov
- Division of Cancer and Stem Cells, University of Nottingham Biodiscovery Institute, United Kingdom (A.K.)
| | - Peter T. Wright
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
- School of Life and Health Sciences, University of Roehampton, United Kingdom (P.T.W.)
| | - Pamela Swiatlowska
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Viacheslav O. Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center, Hamburg-Eppendorf, Germany (H.S., V.O.N.)
| | - Beata Wojciak-Stothard
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Aleksandar P. Ivanov
- Department of Chemistry (Z.K., B.P.N., A.P.I., J.B.E.), Imperial College London, United Kingdom
| | - Joshua B. Edel
- Department of Chemistry (Z.K., B.P.N., A.P.I., J.B.E.), Imperial College London, United Kingdom
| | - Julia Gorelik
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
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10
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Gómez-Viquez NL, Balderas-Villalobos J, Bello-Sánchez MD, Mayorga-Luna M, Mailloux-Salinas P, García-Castañeda M, Ríos-Pérez EB, Mártinez-Ávila MA, Camacho-Castillo LDC, Bravo G, Ávila G, Altamirano J, Carvajal K. Oxidative stress in early metabolic syndrome impairs cardiac RyR2 and SERCA2a activity and modifies the interplay of these proteins during Ca 2+ waves. Arch Physiol Biochem 2023; 129:1058-1070. [PMID: 33689540 DOI: 10.1080/13813455.2021.1895224] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 02/19/2021] [Indexed: 10/21/2022]
Abstract
We investigated how oxidative stress (OS) alters Ca2+ handling in ventricular myocytes in early metabolic syndrome (MetS) in sucrose-fed rats. The effects of N-acetyl cysteine (NAC) or dl-Dithiothreitol (DTT) on systolic Ca2+ transients (SCaTs), diastolic Ca2+ sparks (CaS) and Ca2+ waves (CaW), recorded by confocal techniques, and L-type Ca2+ current (ICa), assessed by whole-cell patch clamp, were evaluated in MetS and Control cells. MetS myocytes exhibited decreased SCaTs and CaS frequency but unaffected CaW propagation. In Control cells, NAC/DTT reduced RyR2/SERCA2a activity blunting SCaTs, CaS frequency and CaW propagation, suggesting that basal ROS optimised Ca2+ signalling by maintaining RyR2/SERCA2a function and that these proteins facilitate CaW propagation. Conversely, NAC/DTT in MetS recovered RyR2/SERCA2a function, improving SCaTs and CaS frequency, but unexpectedly decreasing CaW propagation. We hypothesised that OS decreases RyR2/SERCA2a activity at early MetS, and while decreased SERCA2a favours CaW propagation, diminished RyR2 restrains it.
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Affiliation(s)
- Norma Leticia Gómez-Viquez
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados-Instituto Politécnico Nacional, Ciudad de México, México
| | - Jaime Balderas-Villalobos
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados-Instituto Politécnico Nacional, Ciudad de México, México
- Laboratorio de Nutrición Experimental, Instituto Nacional de Pediatría, Ciudad de México, México
| | - Ma Dolores Bello-Sánchez
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados-Instituto Politécnico Nacional, Ciudad de México, México
| | - Maritza Mayorga-Luna
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados-Instituto Politécnico Nacional, Ciudad de México, México
| | - Patrick Mailloux-Salinas
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados-Instituto Politécnico Nacional, Ciudad de México, México
| | - Maricela García-Castañeda
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados-Instituto Politécnico Nacional, Ciudad de México, México
| | - Erick Benjamín Ríos-Pérez
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados-Instituto Politécnico Nacional, Ciudad de México, México
| | | | | | - Guadalupe Bravo
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados-Instituto Politécnico Nacional, Ciudad de México, México
| | - Guillermo Ávila
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados-Instituto Politécnico Nacional, Ciudad de México, México
| | - Julio Altamirano
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, México
| | - Karla Carvajal
- Laboratorio de Nutrición Experimental, Instituto Nacional de Pediatría, Ciudad de México, México
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11
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Li J, Richmond B, Cluntun AA, Bia R, Walsh MA, Shaw K, Symons JD, Franklin S, Rutter J, Funai K, Shaw RM, Hong T. Cardiac gene therapy treats diabetic cardiomyopathy and lowers blood glucose. JCI Insight 2023; 8:e166713. [PMID: 37639557 PMCID: PMC10561727 DOI: 10.1172/jci.insight.166713] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 08/15/2023] [Indexed: 08/31/2023] Open
Abstract
Diabetic cardiomyopathy, an increasingly global epidemic and a major cause of heart failure with preserved ejection fraction (HFpEF), is associated with hyperglycemia, insulin resistance, and intracardiomyocyte calcium mishandling. Here we identify that, in db/db mice with type 2 diabetes-induced HFpEF, abnormal remodeling of cardiomyocyte transverse-tubule microdomains occurs with downregulation of the membrane scaffolding protein cardiac bridging integrator 1 (cBIN1). Transduction of cBIN1 by AAV9 gene therapy can restore transverse-tubule microdomains to normalize intracellular distribution of calcium-handling proteins and, surprisingly, glucose transporter 4 (GLUT4). Cardiac proteomics revealed that AAV9-cBIN1 normalized components of calcium handling and GLUT4 translocation machineries. Functional studies further identified that AAV9-cBIN1 normalized insulin-dependent glucose uptake in diabetic cardiomyocytes. Phenotypically, AAV9-cBIN1 rescued cardiac lusitropy, improved exercise intolerance, and ameliorated hyperglycemia in diabetic mice. Restoration of transverse-tubule microdomains can improve cardiac function in the setting of diabetic cardiomyopathy and can also improve systemic glycemic control.
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Affiliation(s)
- Jing Li
- Department of Pharmacology and Toxicology, College of Pharmacy
- Nora Eccles Harrison Cardiovascular Research and Training Institute
| | | | | | - Ryan Bia
- Nora Eccles Harrison Cardiovascular Research and Training Institute
| | - Maureen A. Walsh
- College of Health, Department of Nutrition and Integrative Physiology, Program in Molecular Medicine
| | - Kikuyo Shaw
- Department of Pharmacology and Toxicology, College of Pharmacy
| | - J. David Symons
- College of Health, Department of Nutrition and Integrative Physiology, Program in Molecular Medicine
- Diabetes & Metabolism Research Center, and
| | - Sarah Franklin
- Nora Eccles Harrison Cardiovascular Research and Training Institute
| | - Jared Rutter
- Department of Biochemistry
- College of Health, Department of Nutrition and Integrative Physiology, Program in Molecular Medicine
- Diabetes & Metabolism Research Center, and
- Howard Hughes Medical Institute, University of Utah, Salt Lake City, Utah, USA
| | - Katsuhiko Funai
- College of Health, Department of Nutrition and Integrative Physiology, Program in Molecular Medicine
- Diabetes & Metabolism Research Center, and
| | - Robin M. Shaw
- Nora Eccles Harrison Cardiovascular Research and Training Institute
| | - TingTing Hong
- Department of Pharmacology and Toxicology, College of Pharmacy
- Nora Eccles Harrison Cardiovascular Research and Training Institute
- Howard Hughes Medical Institute, University of Utah, Salt Lake City, Utah, USA
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12
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Tamkus G, Uchida K, Lopatin AN. T-tubule recovery after detubulation in isolated mouse cardiomyocytes. Physiol Rep 2023; 11:e15779. [PMID: 37537144 PMCID: PMC10400551 DOI: 10.14814/phy2.15779] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 07/14/2023] [Accepted: 07/14/2023] [Indexed: 08/05/2023] Open
Abstract
Remodeling of cardiac t-tubules in normal and pathophysiological conditions is an important process contributing to the functional performance of the heart. While it is well documented that deterioration of t-tubule network associated with various pathological conditions can be reversed under certain conditions, the mechanistic understanding of the recovery process is essentially lacking. Accordingly, in this study we investigated some aspects of the recovery of t-tubules after experimentally-induced detubulation. T-tubules of isolated mouse ventricular myocytes were first sealed using osmotic shock approach, and their recovery under various experimental conditions was then characterized using electrophysiologic and imaging techniques. The data show that t-tubule recovery is a strongly temperature-dependent process involving reopening of previously collapsed t-tubular segments. T-tubule recovery is slowed by (1) metabolic inhibition of cells, (2) reducing influx of extracellular Ca2+ as well as by (3) both stabilization and disruption of microtubules. Overall, the data show that t-tubule recovery is a highly dynamic process involving several central intracellular structures and processes and lay the basis for more detailed investigations in this area.
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Affiliation(s)
- Greta Tamkus
- Department of Molecular and Integrative PhysiologyUniversity of MichiganAnn ArborMichiganUSA
- Present address:
John T. Milliken Department of MedicineWashington University School of MedicineSt. LouisMissouriUSA
| | - Keita Uchida
- Department of Molecular and Integrative PhysiologyUniversity of MichiganAnn ArborMichiganUSA
- Present address:
Department of PhysiologyPennsylvania Muscle Institute, University of Pennsylvania, Perelman School of MedicinePhiladelphiaPennsylvaniaUSA
| | - Anatoli N. Lopatin
- Department of Molecular and Integrative PhysiologyUniversity of MichiganAnn ArborMichiganUSA
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13
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Kermani F, Mosqueira M, Peters K, Lemma ED, Rapti K, Grimm D, Bastmeyer M, Laugsch M, Hecker M, Ullrich ND. Membrane remodelling triggers maturation of excitation-contraction coupling in 3D-shaped human-induced pluripotent stem cell-derived cardiomyocytes. Basic Res Cardiol 2023; 118:13. [PMID: 36988697 PMCID: PMC10060306 DOI: 10.1007/s00395-023-00984-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 03/14/2023] [Accepted: 03/14/2023] [Indexed: 03/30/2023]
Abstract
The prospective use of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) for cardiac regenerative medicine strongly depends on the electro-mechanical properties of these cells, especially regarding the Ca2+-dependent excitation-contraction (EC) coupling mechanism. Currently, the immature structural and functional features of hiPSC-CM limit the progression towards clinical applications. Here, we show that a specific microarchitecture is essential for functional maturation of hiPSC-CM. Structural remodelling towards a cuboid cell shape and induction of BIN1, a facilitator of membrane invaginations, lead to transverse (t)-tubule-like structures. This transformation brings two Ca2+ channels critical for EC coupling in close proximity, the L-type Ca2+ channel at the sarcolemma and the ryanodine receptor at the sarcoplasmic reticulum. Consequently, the Ca2+-dependent functional interaction of these channels becomes more efficient, leading to improved spatio-temporal synchronisation of Ca2+ transients and higher EC coupling gain. Thus, functional maturation of hiPSC-cardiomyocytes by optimised cell microarchitecture needs to be considered for future cardiac regenerative approaches.
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Affiliation(s)
- Fatemeh Kermani
- Department of Cardiovascular Physiology, Heidelberg University, Heidelberg, Germany
| | - Matias Mosqueira
- Department of Cardiovascular Physiology, Heidelberg University, Heidelberg, Germany
| | - Kyra Peters
- Department of Cardiovascular Physiology, Heidelberg University, Heidelberg, Germany
| | - Enrico D Lemma
- Zoological Institute, Cell and Neurobiology, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Department of Engineering, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Kleopatra Rapti
- Department of Infectious Diseases/Virology, Section Viral Vector Technologies, Heidelberg University, Heidelberg, Germany
| | - Dirk Grimm
- Department of Infectious Diseases/Virology, Section Viral Vector Technologies, Heidelberg University, Heidelberg, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Heidelberg/Mannheim, Heidelberg, Germany
- German Center for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Martin Bastmeyer
- Zoological Institute, Cell and Neurobiology, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Institute of Biological and Chemical Systems-Biological information processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
- Research Bridge (Synthetic Biology), Heidelberg-Karlsruhe Research Partnership (HEiKA), Heidelberg University and Karlsruhe Institute of Technology, Heidelberg, Germany
| | - Magdalena Laugsch
- Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - Markus Hecker
- Department of Cardiovascular Physiology, Heidelberg University, Heidelberg, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Heidelberg/Mannheim, Heidelberg, Germany
| | - Nina D Ullrich
- Department of Cardiovascular Physiology, Heidelberg University, Heidelberg, Germany.
- German Center for Cardiovascular Research (DZHK), Partner Site Heidelberg/Mannheim, Heidelberg, Germany.
- Research Bridge (Synthetic Biology), Heidelberg-Karlsruhe Research Partnership (HEiKA), Heidelberg University and Karlsruhe Institute of Technology, Heidelberg, Germany.
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14
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Xu X, Elkenani M, Tan X, Hain JK, Cui B, Schnelle M, Hasenfuss G, Toischer K, Mohamed BA. DNA Methylation Analysis Identifies Novel Epigenetic Loci in Dilated Murine Heart upon Exposure to Volume Overload. Int J Mol Sci 2023; 24:ijms24065885. [PMID: 36982963 PMCID: PMC10059258 DOI: 10.3390/ijms24065885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/14/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
Left ventricular (LV) dilatation, a prominent risk factor for heart failure (HF), precedes functional deterioration and is used to stratify patients at risk for arrhythmias and cardiac mortality. Aberrant DNA methylation contributes to maladaptive cardiac remodeling and HF progression following pressure overload and ischemic cardiac insults. However, no study has examined cardiac DNA methylation upon exposure to volume overload (VO) despite being relatively common among HF patients. We carried out global methylome analysis of LV harvested at a decompensated HF stage following exposure to VO induced by aortocaval shunt. VO resulted in pathological cardiac remodeling, characterized by massive LV dilatation and contractile dysfunction at 16 weeks after shunt. Although methylated DNA was not markedly altered globally, 25 differentially methylated promoter regions (DMRs) were identified in shunt vs. sham hearts (20 hypermethylated and 5 hypomethylated regions). The validated hypermethylated loci in Junctophilin-2 (Jph2), Signal peptidase complex subunit 3 (Spcs3), Vesicle-associated membrane protein-associated protein B (Vapb), and Inositol polyphosphate multikinase (Ipmk) were associated with the respective downregulated expression and were consistently observed in dilated LV early after shunt at 1 week after shunt, before functional deterioration starts to manifest. These hypermethylated loci were also detected peripherally in the blood of the shunt mice. Altogether, we have identified conserved DMRs that could be novel epigenetic biomarkers in dilated LV upon VO exposure.
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Affiliation(s)
- Xingbo Xu
- Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075 Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), 37075 Göttingen, Germany
| | - Manar Elkenani
- Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075 Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), 37075 Göttingen, Germany
- Department of Clinical Pathology, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Xiaoying Tan
- DZHK (German Centre for Cardiovascular Research), 37075 Göttingen, Germany
- Department of Nephrology and Rheumatology, University Medical Center of Göttingen, 37075 Göttingen, Germany
| | - Jara Katharina Hain
- Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Baolong Cui
- Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075 Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), 37075 Göttingen, Germany
| | - Moritz Schnelle
- DZHK (German Centre for Cardiovascular Research), 37075 Göttingen, Germany
- Department of Clinical Chemistry, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Gerd Hasenfuss
- Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075 Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), 37075 Göttingen, Germany
| | - Karl Toischer
- Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075 Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), 37075 Göttingen, Germany
| | - Belal A Mohamed
- Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075 Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), 37075 Göttingen, Germany
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15
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Dixon RE, Trimmer JS. Endoplasmic Reticulum-Plasma Membrane Junctions as Sites of Depolarization-Induced Ca 2+ Signaling in Excitable Cells. Annu Rev Physiol 2023; 85:217-243. [PMID: 36202100 PMCID: PMC9918718 DOI: 10.1146/annurev-physiol-032122-104610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Membrane contact sites between endoplasmic reticulum (ER) and plasma membrane (PM), or ER-PM junctions, are found in all eukaryotic cells. In excitable cells they play unique roles in organizing diverse forms of Ca2+ signaling as triggered by membrane depolarization. ER-PM junctions underlie crucial physiological processes such as excitation-contraction coupling, smooth muscle contraction and relaxation, and various forms of activity-dependent signaling and plasticity in neurons. In many cases the structure and molecular composition of ER-PM junctions in excitable cells comprise important regulatory feedback loops linking depolarization-induced Ca2+ signaling at these sites to the regulation of membrane potential. Here, we describe recent findings on physiological roles and molecular composition of native ER-PM junctions in excitable cells. We focus on recent studies that provide new insights into canonical forms of depolarization-induced Ca2+ signaling occurring at junctional triads and dyads of striated muscle, as well as the diversity of ER-PM junctions in these cells and in smooth muscle and neurons.
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Affiliation(s)
- Rose E Dixon
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, California, USA;
| | - James S Trimmer
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, California, USA;
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16
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Zou J, Wang W, Lu Y, Ayala J, Dong K, Zhou H, Wang J, Chen W, Weintraub NL, Zhou J, Li J, Su H. Neddylation is required for perinatal cardiac development through stimulation of metabolic maturation. Cell Rep 2023; 42:112018. [PMID: 36662623 PMCID: PMC10029150 DOI: 10.1016/j.celrep.2023.112018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 11/23/2022] [Accepted: 01/05/2023] [Indexed: 01/21/2023] Open
Abstract
Cardiac maturation is crucial for postnatal cardiac development and is increasingly known to be regulated by a series of transcription factors. However, post-translational mechanisms regulating this process remain unclear. Here we report the indispensable role of neddylation in cardiac maturation. Mosaic deletion of NAE1, an essential enzyme for neddylation, in neonatal hearts results in the rapid development of cardiomyopathy and heart failure. NAE1 deficiency disrupts transverse tubule formation, inhibits physiological hypertrophy, and represses fetal-to-adult isoform switching, thus culminating in cardiomyocyte immaturation. Mechanistically, we find that neddylation is needed for the perinatal metabolic transition from glycolytic to oxidative metabolism in cardiomyocytes. Further, we show that HIF1α is a putative neddylation target and that inhibition of neddylation accumulates HIF1α and impairs fatty acid utilization and bioenergetics in cardiomyocytes. Together, our data show neddylation is required for cardiomyocyte maturation through promoting oxidative metabolism in the developing heart.
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Affiliation(s)
- Jianqiu Zou
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Wenjuan Wang
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; Key Laboratory of Protein Modification and Degradation, State Key Laboratory of Respiratory Disease, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, Guangdong 511436, China
| | - Yi Lu
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; Department of Neurology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China
| | - Juan Ayala
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Kunzhe Dong
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Hongyi Zhou
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Jinxi Wang
- Department of Medicine, University of Iowa, 200 Hawkins Drive, CBRB 2270B, Iowa City, IA 52242, USA
| | - Weiqin Chen
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Neal L Weintraub
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Jiliang Zhou
- Department of Medicine, University of Iowa, 200 Hawkins Drive, CBRB 2270B, Iowa City, IA 52242, USA
| | - Jie Li
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; Division of Cardiology, Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Huabo Su
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
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17
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Abstract
Cardiac alternans arises from dynamical instabilities in the electrical and calcium cycling systems of the heart, and often precedes ventricular arrhythmias and sudden cardiac death. In this review, we integrate clinical observations with theory and experiment to paint a holistic portrait of cardiac alternans: the underlying mechanisms, arrhythmic manifestations and electrocardiographic signatures. We first summarize the cellular and tissue mechanisms of alternans that have been demonstrated both theoretically and experimentally, including 3 voltage-driven and 2 calcium-driven alternans mechanisms. Based on experimental and simulation results, we describe their relevance to mechanisms of arrhythmogenesis under different disease conditions, and their link to electrocardiographic characteristics of alternans observed in patients. Our major conclusion is that alternans is not only a predictor, but also a causal mechanism of potentially lethal ventricular and atrial arrhythmias across the full spectrum of arrhythmia mechanisms that culminate in functional reentry, although less important for anatomic reentry and focal arrhythmias.
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Affiliation(s)
- Zhilin Qu
- Departments of Medicine (Cardiology), Physiology, and Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA
| | - James N. Weiss
- Departments of Medicine (Cardiology), Physiology, and Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA
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18
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Del Rivero Morfin PJ, Marx SO, Ben-Johny M. Sympathetic Nervous System Regulation of Cardiac Calcium Channels. Handb Exp Pharmacol 2023. [PMID: 36592229 DOI: 10.1007/164_2022_632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Calcium influx through voltage-gated calcium channels, Cav1.2, in cardiomyocytes initiates excitation-contraction coupling in the heart. The force and rate of cardiac contraction are modulated by the sympathetic nervous system, mediated substantially by changes in intracellular calcium. Norepinephrine released from sympathetic neurons innervating the heart and epinephrine secreted by the adrenal chromaffin cells bind to β-adrenergic receptors on the sarcolemma of cardiomyocytes initiating a signaling cascade that generates cAMP and activates protein kinase A, the targets of which control calcium influx. For decades, the mechanisms by which PKA regulated calcium channels in the heart were not known. Recently, these mechanisms have been elucidated. In this chapter, we will review the history of the field and the studies that led to the identification of the evolutionarily conserved process.
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Affiliation(s)
- Pedro J Del Rivero Morfin
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Steven O Marx
- Division of Cardiology, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA. .,Department of Pharmacology and Molecular Signaling, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
| | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
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19
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Díaz-Vesga MC, Flores-Vergara R, Riquelme JA, Llancaqueo M, Sánchez G, Vergara C, Michea L, Donoso P, Quest AFG, Olmedo I, Pedrozo Z. Polycystin-1 Is a Crucial Regulator of BIN1 Expression and T-Tubule Remodeling Associated with the Development of Dilated Cardiomyopathy. Int J Mol Sci 2022; 24. [PMID: 36614108 DOI: 10.3390/ijms24010667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/20/2022] [Accepted: 12/24/2022] [Indexed: 01/03/2023] Open
Abstract
Cardiomyopathy is commonly observed in patients with autosomal dominant polycystic kidney disease (ADPKD), even when they have normal renal function and arterial pressure. The role of cardiomyocyte polycystin-1 (PC1) in cardiovascular pathophysiology remains unknown. PC1 is a potential regulator of BIN1 that maintains T-tubule structure, and alterations in BIN1 expression induce cardiac pathologies. We used a cardiomyocyte-specific PC1-silenced (PC1-KO) mouse model to explore the relevance of cardiomyocyte PC1 in the development of heart failure (HF), considering reduced BIN1 expression induced T-tubule remodeling as a potential mechanism. PC1-KO mice exhibited an impairment of cardiac function, as measured by echocardiography, but no signs of HF until 7-9 months of age. Of the PC1-KO mice, 43% died suddenly at 7 months of age, and 100% died after 9 months with dilated cardiomyopathy. Total BIN1 mRNA, protein levels, and its localization in plasma membrane-enriched fractions decreased in PC1-KO mice. Moreover, the BIN1 + 13 isoform decreased while the BIN1 + 13 + 17 isoform was overexpressed in mice without signs of HF. However, BIN1 + 13 + 17 overexpression was not observed in mice with HF. T-tubule remodeling and BIN1 score measured in plasma samples were associated with decreased PC1-BIN1 expression and HF development. Our results show that decreased PC1 expression in cardiomyocytes induces dilated cardiomyopathy associated with diminished BIN1 expression and T-tubule remodeling. In conclusion, positive modulation of BIN1 expression by PC1 suggests a novel pathway that may be relevant to understanding the pathophysiological mechanisms leading to cardiomyopathy in ADPKD patients.
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20
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Barndt RJ, Liu Q, Tang Y, Haugh MP, Cui J, Chan SY, Wu H. Metabolic Maturation Exaggerates Abnormal Calcium Handling in a Lamp2 Knockout Human Pluripotent Stem Cell-Derived Cardiomyocyte Model of Danon Disease. Biomolecules 2022; 13:biom13010069. [PMID: 36671453 PMCID: PMC9855424 DOI: 10.3390/biom13010069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 12/27/2022] [Accepted: 12/27/2022] [Indexed: 01/01/2023] Open
Abstract
Danon disease (DD) is caused by mutations of the gene encoding lysosomal-associated membrane protein type 2 (LAMP2), which lead to impaired autophagy, glycogen accumulation, and cardiac hypertrophy. However, it is not well understood why a large portion of DD patients develop arrhythmia and sudden cardiac death. In the current study, we generated LAMP2 knockout (KO) human iPSC-derived cardiomyocytes (CM), which mimic the LAMP2 dysfunction in DD heart. Morphologic analysis demonstrated the sarcomere disarrangement in LAMP2 KO CMs. In functional studies, LAMP2 KO CMs showed near-normal calcium handling at base level. However, treatment of pro-maturation medium (MM) exaggerated the disease phenotype in the KO cells as they exhibited impaired calcium recycling and increased irregular beating events, which recapitulates the pro-arrhythmia phenotypes of DD patients. Further mechanistic study confirmed that MM treatment significantly enhanced the autophagic stress in the LAMP2 KO CMs, which was accompanied by an increase of both cellular and mitochondrial reactive oxygen species (ROS) levels. Excess ROS accumulation in LAMP2 KO CMs resulted in the over-activation of calcium/calmodulin dependent protein kinase IIδ (CaMKIIδ) and arrhythmogenesis, which was partially rescued by the treatment of ROS scavenger. In summary, our study has revealed ROS induced CaMKIIδ overactivation as a key mechanism that promotes cardiac arrhythmia in DD patients.
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Affiliation(s)
- Robert J. Barndt
- Pittsburgh Heart, Lung, and Blood Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Qing Liu
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
- Center for Human Genetics, Clemson University, Greenwood, SC 29646, USA
| | - Ying Tang
- Pittsburgh Heart, Lung, and Blood Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Michael P. Haugh
- Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15213, USA
| | - Jeffery Cui
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Stephen Y. Chan
- Pittsburgh Heart, Lung, and Blood Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Division of Cardiology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Haodi Wu
- Pittsburgh Heart, Lung, and Blood Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15213, USA
- Division of Cardiology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Correspondence:
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21
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Abstract
PURPOSE OF THE REVIEW Dyssynchrony occurs when portions of the cardiac chambers contract in an uncoordinated fashion. Ventricular dyssynchrony primarily impacts the left ventricle and may result in heart failure. This entity is recognized as a major contributor to the development and progression of heart failure. A hallmark of dyssynchronous heart failure (HFd) is left ventricular recovery after dyssynchrony is corrected. This review discusses the current understanding of pathophysiology of HFd and provides clinical examples and current techniques for treatment. RECENT FINDINGS Data show that HFd responds poorly to medical therapy. Cardiac resynchronization therapy (CRT) in the form of conventional biventricular pacing (BVP) is of proven benefit in HFd, but is limited by a significant non-responder rate. Recently, conduction system pacing (His bundle or left bundle branch area pacing) has also shown promise in correcting HFd. HFd should be recognized as a distinct etiology of heart failure; HFd responds best to CRT.
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Affiliation(s)
- Sean J Dikdan
- Thomas Jefferson University Hospital, Philadelphia, PA, 19107, USA
| | | | - Behzad B Pavri
- Thomas Jefferson University Hospital, Philadelphia, PA, 19107, USA.
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22
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Perera T, Pius C, Niort B, Radcliffe EJ, Dibb KM, Trafford AW, Pinali C. Serial block face scanning electron microscopy reveals region-dependent remodelling of transverse tubules post-myocardial infarction. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210331. [PMID: 36189812 PMCID: PMC9527908 DOI: 10.1098/rstb.2021.0331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The highly organized transverse tubule (t-tubule) network facilitates cardiac excitation-contraction coupling and synchronous cardiac myocyte contraction. In cardiac failure secondary to myocardial infarction (MI), changes in the structure and organization of t-tubules result in impaired cardiac contractility. However, there is still little knowledge on the regional variation of t-tubule remodelling in cardiac failure post-MI. Here, we investigate post-MI t-tubule remodelling in infarct border and remote regions, using serial block face scanning electron microscopy (SBF-SEM) applied to a translationally relevant sheep ischaemia reperfusion MI model and matched controls. We performed minimally invasive coronary angioplasty of the left anterior descending artery, followed by reperfusion after 90 min to establish the MI model. Left ventricular tissues obtained from control and MI hearts eight weeks post-MI were imaged using SBF-SEM. Image analysis generated three-dimensional reconstructions of the t-tubular network in control, MI border and remote regions. Quantitative analysis revealed that the MI border region was characterized by t-tubule depletion and fragmentation, dilation of surviving t-tubules and t-tubule elongation. This study highlights region-dependent remodelling of the tubular network post-MI and may provide novel localized therapeutic targets aimed at preservation or restoration of the t-tubules to manage cardiac contractility post-MI. This article is part of the theme issue 'The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease'.
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Affiliation(s)
- Tharushi Perera
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, 46 Grafton Street, Manchester M13 9NT, UK
| | - Charlene Pius
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, 46 Grafton Street, Manchester M13 9NT, UK
| | - Barbara Niort
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, 46 Grafton Street, Manchester M13 9NT, UK
| | - Emma J Radcliffe
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, 46 Grafton Street, Manchester M13 9NT, UK
| | - Katharine M Dibb
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, 46 Grafton Street, Manchester M13 9NT, UK
| | - Andrew W Trafford
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, 46 Grafton Street, Manchester M13 9NT, UK
| | - Christian Pinali
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, 46 Grafton Street, Manchester M13 9NT, UK
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23
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Frisk M, Norseng PA, Stenersen Espe EK, Louch WE. Tubulator: an automated approach to analysis of t-tubule and dyadic organization in cardiomyocytes. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210468. [PMID: 36189810 PMCID: PMC9527907 DOI: 10.1098/rstb.2021.0468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
During cardiac disease, t-tubules and dyads are remodelled and disrupted within cardiomyocytes, thereby reducing cardiac performance. Given the pathological implications of such dyadic remodelling, robust and versatile tools for characterizing these sub-cellular structures are needed. While analysis programs for continuous and regular structures such as rodent ventricular t-tubules are available, at least in two dimensions, these approaches are less appropriate for assessment of more irregular structures, such as dyadic proteins and non-rodent t-tubules. Here, we demonstrate versatile, easy-to-use software that performs such analyses. This software, called Tubulator, enables automated analysis of t-tubules and dyadic proteins alike, in both tissue sections and isolated myocytes. The program measures densities of subcellular structures and proteins in individual cells, quantifies their distribution into transversely and longitudinally oriented elements, and supports detailed co-localization analyses. Importantly, Tubulator provides tools for three-dimensional assessment and rendering of image stacks, extending examinations from the single plane to the whole-myocyte level. To provide insight into the consequences of dyadic organization for synchrony of Ca2+ handling, Tubulator also creates 'distance maps', by calculating the distance from all cytosolic positions to the nearest t-tubule and/or dyad. In conclusion, this freely accessible program provides detailed automated analysis of the three-dimensional nature of dyadic and t-tubular structures. This article is part of the theme issue 'The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease'.
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Affiliation(s)
- Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway.,K.G. Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - Per Andreas Norseng
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway.,K.G. Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - Emil Knut Stenersen Espe
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway.,K.G. Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway.,K.G. Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
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24
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Holmes M, Hurley ME, Sheard TMD, Benson AP, Jayasinghe I, Colman MA. Increased SERCA2a sub-cellular heterogeneity in right-ventricular heart failure inhibits excitation-contraction coupling and modulates arrhythmogenic dynamics. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210317. [PMID: 36189801 PMCID: PMC9527927 DOI: 10.1098/rstb.2021.0317] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/21/2021] [Indexed: 12/14/2022] Open
Abstract
The intracellular calcium handling system of cardiomyocytes is responsible for controlling excitation-contraction coupling (ECC) and has been linked to pro-arrhythmogenic cellular phenomena in conditions such as heart failure (HF). SERCA2a, responsible for intracellular uptake, is a primary regulator of calcium homeostasis, and remodelling of its function has been proposed as a causal factor underlying cellular and tissue dysfunction in disease. Whereas adaptations to the global (i.e. whole-cell) expression of SERCA2a have been previously investigated in the context of multiple diseases, the role of its spatial profile in the sub-cellular volume has yet to be elucidated. We present an approach to characterize the sub-cellular heterogeneity of SERCA2a and apply this approach to quantify adaptations to the length-scale of heterogeneity (the distance over which expression is correlated) associated with right-ventricular (RV)-HF. These characterizations informed simulations to predict the functional implications of this heterogeneity, and its remodelling in disease, on ECC, the dynamics of calcium-transient alternans and the emergence of spontaneous triggered activity. Image analysis reveals that RV-HF is associated with an increase in length-scale and its inter-cellular variability; simulations predict that this increase in length-scale can reduce ECC and critically modulate the vulnerability to both alternans and triggered activity. This article is part of the theme issue 'The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease'.
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Affiliation(s)
- M. Holmes
- Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - M. E. Hurley
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - T. M. D. Sheard
- School of Biosciences, The University of Sheffield, Sheffield S10 2TN, UK
| | - A. P. Benson
- Institute of Membrane and Systems Biology, University of Leeds, Leeds LS2 9JT, UK
| | - I. Jayasinghe
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
- School of Biosciences, The University of Sheffield, Sheffield S10 2TN, UK
| | - M. A. Colman
- Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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25
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Ji XY, Zheng D, Ni R, Wang JX, Shao JQ, Vue Z, Hinton A, Song LS, Fan GC, Chakrabarti S, Su ZL, Peng TQ. Sustained over-expression of calpain-2 induces age-dependent dilated cardiomyopathy in mice through aberrant autophagy. Acta Pharmacol Sin 2022; 43:2873-2884. [PMID: 35986214 PMCID: PMC9622835 DOI: 10.1038/s41401-022-00965-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 07/24/2022] [Indexed: 11/09/2022] Open
Abstract
Calpains have been implicated in heart diseases. While calpain-1 has been detrimental to the heart, the role of calpain-2 in cardiac pathology remains controversial. In this study we investigated whether sustained over-expression of calpain-2 had any adverse effects on the heart and the underlying mechanisms. Double transgenic mice (Tg-Capn2/tTA) were generated, which express human CAPN2 restricted to cardiomyocytes. The mice were subjected to echocardiography at age 3, 6, 8 and 12 months, and their heart tissues and sera were collected for analyses. We showed that transgenic mice over-expressing calpain-2 restricted to cardiomyocytes had normal heart function with no evidence of cardiac pathological remodeling at age 3 months. However, they exhibited features of dilated cardiomyopathy including increased heart size, enlarged heart chambers and heart dysfunction from age 8 months; histological analysis revealed loss of cardiomyocytes replaced by myocardial fibrosis and cardiomyocyte hypertrophy in transgenic mice from age 8 months. These cardiac alterations closely correlated with aberrant autophagy evidenced by significantly increased LC3BII and p62 protein levels and accumulation of autophagosomes in the hearts of transgenic mice. Notably, injection of 3-methyladenine, a well-established inhibitor of autophagy (30 mg/kg, i.p. once every 3 days starting from age 6 months for 2 months) prevented aberrant autophagy, attenuated myocardial injury and improved heart function in the transgenic mice. In cultured cardiomyocytes, over-expression of calpain-2 blocked autophagic flux by impairing lysosomal function. Furthermore, over-expression of calpain-2 resulted in lower levels of junctophilin-2 protein in the heart of transgenic mice and in cultured cardiomyocytes, which was attenuated by 3-methyladenine. In addition, blockade of autophagic flux by bafilomycin A (100 nM) induced a reduction of junctophilin-2 protein in cardiomyocytes. In summary, transgenic over-expression of calpain-2 induces age-dependent dilated cardiomyopathy in mice, which may be mediated through aberrant autophagy and a reduction of junctophilin-2. Thus, a sustained increase in calpain-2 may be detrimental to the heart.
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Affiliation(s)
- Xiao-Yun Ji
- International Genome Center, Jiangsu University, Zhenjiang, 212013, China
- Lawson Health Research Institute, London Health Sciences Centre, London, ON, N6A 5W9, Canada
- Department of Pathology and Laboratory Medicine, Western University, London, ON, N6A 5C1, Canada
| | - Dong Zheng
- Centre of Clinical Laboratory, the First Affiliated Hospital of Soochow University, Suzhou, 215006, China
| | - Rui Ni
- Lawson Health Research Institute, London Health Sciences Centre, London, ON, N6A 5W9, Canada
- Department of Pathology and Laboratory Medicine, Western University, London, ON, N6A 5C1, Canada
| | - Jin-Xi Wang
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Jian-Qiang Shao
- Central Microscopy Research Facility, University of Iowa, Iowa City, IA, 52242, USA
| | - Zer Vue
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Antentor Hinton
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Long-Sheng Song
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Guo-Chang Fan
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Subrata Chakrabarti
- Department of Pathology and Laboratory Medicine, Western University, London, ON, N6A 5C1, Canada
| | - Zhao-Liang Su
- International Genome Center, Jiangsu University, Zhenjiang, 212013, China.
| | - Tian-Qing Peng
- Lawson Health Research Institute, London Health Sciences Centre, London, ON, N6A 5W9, Canada.
- Department of Pathology and Laboratory Medicine, Western University, London, ON, N6A 5C1, Canada.
- Department of Medicine, Western University, London, ON, N6A 5W9, Canada.
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26
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Yu L, Hall DD, Zhao W, Song LS. NMR resonance assignments of the DNA binding domain of mouse Junctophilin-2. Biomol NMR Assign 2022; 16:273-279. [PMID: 35665900 PMCID: PMC10394741 DOI: 10.1007/s12104-022-10091-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
Junctophilin-2 (JP2) is a critical structural protein in the heart by stabilizing junctional membrane complexes between the plasma membrane and sarcoplasmic reticula responsible for precise Ca2+ regulation. Such complexes are essential for efficient cardiomyocyte contraction and adaptation to altered cardiac workload conditions. Mutations in the JPH2 gene that encodes JP2 are associated with inherited cardiomyopathies and arrhythmias, and disruption of JP2 function is lethal. Interestingly, cardiac stress promotes the proteolytic cleavage of JP2 that triggers the translocation of its N-terminal fragment into the nucleus to repress maladaptive gene transcription. We previously found that the central region of JP2 is responsible for mediating direct DNA binding interactions. Recent structural studies indicate that this region serves as a structural role in the cytosolic form of JP2 by folding into a single continuous α-helix. However, the structural basis of how this DNA-binding domain interacts with DNA is not known. Here, we report the backbone and sidechain assignments of the DNA-binding domain (residues 331-413) of mouse JP2. These assignments reveal that the JP2 DNA binding domain is an intrinsically disordered protein and contains two α-helices located in the C-terminal portion of the protein. Moreover, this protein binds to DNA in a similar manner to that shown previously by electrophoretic mobility shift assays. Therefore, these assignments provide a framework for further structural studies into the interaction of this JP2 domain with DNA for the elucidation of transcriptional regulation of stress-responsive genes as well as its role in the stabilization of junctional membrane complexes.
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Affiliation(s)
- Liping Yu
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, B291, CBRB, 285 Newton Road, Iowa City, IA, 52242, USA.
- CCOM NMR Core Facility, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA.
| | - Duane D Hall
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, 285 Newton Road, Iowa City, IA, 52242, USA
| | - Weiyang Zhao
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, 285 Newton Road, Iowa City, IA, 52242, USA
| | - Long-Sheng Song
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, B291, CBRB, 285 Newton Road, Iowa City, IA, 52242, USA.
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, 285 Newton Road, Iowa City, IA, 52242, USA.
- Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA.
- Iowa City Veterans Affairs Medical Center, Iowa City, IA, 52242, USA.
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27
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Zhang X, Ni H, Morotti S, Smith CER, Sato D, Louch WE, Edwards AG, Grandi E. Mechanisms of spontaneous Ca 2+ release-mediated arrhythmia in a novel 3D human atrial myocyte model: I. Transverse-axial tubule variation. J Physiol 2022. [PMID: 36094888 PMCID: PMC10008525 DOI: 10.1113/jp283363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/02/2022] [Indexed: 11/08/2022] Open
Abstract
Intracellular calcium (Ca2+ ) cycling is tightly regulated in the healthy heart ensuring effective contraction. This is achieved by transverse (t)-tubule membrane invaginations that facilitate close coupling of key Ca2+ -handling proteins such as the L-type Ca2+ channel and Na+ -Ca2+ exchanger (NCX) on the cell surface with ryanodine receptors (RyRs) on the intracellular Ca2+ store. Although less abundant and regular than in the ventricle, t-tubules also exist in atrial myocytes as a network of transverse invaginations with axial extensions known as the transverse-axial tubule system (TATS). In heart failure and atrial fibrillation, there is TATS remodelling that is associated with aberrant Ca2+ -handling and Ca2+ -induced arrhythmic activity; however, the mechanism underlying this is not fully understood. To address this, we developed a novel 3D human atrial myocyte model that couples electrophysiology and Ca2+ -handling with variable TATS organization and density. We extensively parameterized and validated our model against experimental data to build a robust tool examining TATS regulation of subcellular Ca2+ release. We found that varying TATS density and thus the localization of key Ca2+ -handling proteins has profound effects on Ca2+ handling. Following TATS loss, there is reduced NCX that results in increased cleft Ca2+ concentration through decreased Ca2+ extrusion. This elevated Ca2+ increases RyR open probability causing spontaneous Ca2+ releases and the promotion of arrhythmogenic waves (especially in the cell interior) leading to voltage instabilities through delayed afterdepolarizations. In summary, the present study demonstrates a mechanistic link between TATS remodelling and Ca2+ -driven proarrhythmic behaviour that probably reflects the arrhythmogenic state observed in disease. KEY POINTS: Transverse-axial tubule systems (TATS) modulate Ca2+ handling and excitation-contraction coupling in atrial myocytes, with TATS remodelling in heart failure and atrial fibrillation being associated with altered Ca2+ cycling and subsequent arrhythmogenesis. To investigate the poorly understood mechanisms linking TATS variation and spontaneous Ca2+ release, we built, parameterized and validated a 3D human atrial myocyte model coupling electrophysiology and spatially-detailed subcellular Ca2+ handling governed by the TATS. Simulated TATS loss causes diastolic Ca2+ and voltage instabilities through reduced Na+ -Ca2+ exchanger-mediated Ca2+ removal, cleft Ca2+ accumulation and increased ryanodine receptor open probability, resulting in spontaneous Ca2+ release and promotion of arrhythmogenic waves and delayed afterdepolarizations. At fast electrical rates typical of atrial tachycardia/fibrillation, spontaneous Ca2+ releases are larger and more frequent in the cell interior than at the periphery. Our work provides mechanistic insight into how atrial TATS remodelling can lead to Ca2+ -driven instabilities that may ultimately contribute to the arrhythmogenic state in disease.
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Affiliation(s)
- Xianwei Zhang
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Haibo Ni
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Stefano Morotti
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | | | - Daisuke Sato
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Andrew G Edwards
- Department of Pharmacology, University of California Davis, Davis, CA, USA.,Simula Research Laboratory, Lysaker, Norway
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, CA, USA
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28
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Guarina L, Moghbel AN, Pourhosseinzadeh MS, Cudmore RH, Sato D, Clancy CE, Santana LF. Biological noise is a key determinant of the reproducibility and adaptability of cardiac pacemaking and EC coupling. J Gen Physiol 2022; 154:213185. [PMID: 35482009 PMCID: PMC9059386 DOI: 10.1085/jgp.202012613] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 03/16/2022] [Accepted: 04/07/2022] [Indexed: 12/23/2022] Open
Abstract
Each heartbeat begins with the generation of an action potential in pacemaking cells in the sinoatrial node. This signal triggers contraction of cardiac muscle through a process termed excitation-contraction (EC) coupling. EC coupling is initiated in dyadic structures of cardiac myocytes, where ryanodine receptors in the junctional sarcoplasmic reticulum come into close apposition with clusters of CaV1.2 channels in invaginations of the sarcolemma. Cooperative activation of CaV1.2 channels within these clusters causes a local increase in intracellular Ca2+ that activates the juxtaposed ryanodine receptors. A salient feature of healthy cardiac function is the reliable and precise beat-to-beat pacemaking and amplitude of Ca2+ transients during EC coupling. In this review, we discuss recent discoveries suggesting that the exquisite reproducibility of this system emerges, paradoxically, from high variability at subcellular, cellular, and network levels. This variability is attributable to stochastic fluctuations in ion channel trafficking, clustering, and gating, as well as dyadic structure, which increase intracellular Ca2+ variance during EC coupling. Although the effects of these large, local fluctuations in function and organization are sometimes negligible at the macroscopic level owing to spatial-temporal summation within and across cells in the tissue, recent work suggests that the "noisiness" of these intracellular Ca2+ events may either enhance or counterintuitively reduce variability in a context-dependent manner. Indeed, these noisy events may represent distinct regulatory features in the tuning of cardiac contractility. Collectively, these observations support the importance of incorporating experimentally determined values of Ca2+ variance in all EC coupling models. The high reproducibility of cardiac contraction is a paradoxical outcome of high Ca2+ signaling variability at subcellular, cellular, and network levels caused by stochastic fluctuations in multiple processes in time and space. This underlying stochasticity, which counterintuitively manifests as reliable, consistent Ca2+ transients during EC coupling, also allows for rapid changes in cardiac rhythmicity and contractility in health and disease.
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Affiliation(s)
- Laura Guarina
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA
| | - Ariana Neelufar Moghbel
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA
| | | | - Robert H Cudmore
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA
| | - Daisuke Sato
- Department of Pharmacology, University of California Davis School of Medicine, Davis, CA
| | - Colleen E Clancy
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA
| | - Luis Fernando Santana
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA
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29
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Kuo CW, Pratiwi FW, Liu YT, Chueh DY, Chen P. Revealing the nanometric structural changes in myocardial infarction models by time-lapse intravital imaging. Front Bioeng Biotechnol 2022; 10:935415. [PMID: 36051583 PMCID: PMC9424828 DOI: 10.3389/fbioe.2022.935415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
In the development of bioinspired nanomaterials for therapeutic applications, it is very important to validate the design of nanomaterials in the disease models. Therefore, it is desirable to visualize the change of the cells in the diseased site at the nanoscale. Heart diseases often start with structural, morphological, and functional alterations of cardiomyocyte components at the subcellular level. Here, we developed straightforward technique for long-term real-time intravital imaging of contracting hearts without the need of cardiac pacing and complex post processing images to understand the subcellular structural and dynamic changes in the myocardial infarction model. A two-photon microscope synchronized with electrocardiogram signals was used for long-term in vivo imaging of a contracting heart with subcellular resolution. We found that the structural and dynamic behaviors of organelles in cardiomyocytes closely correlated with heart function. In the myocardial infarction model, sarcomere shortening decreased from ∼15% (healthy) to ∼8% (diseased) as a result of impaired cardiac function, whereas the distances between sarcomeres increased by 100 nm (from 2.11 to 2.21 μm) in the diastolic state. In addition, T-tubule system regularity analysis revealed that T-tubule structures that were initially highly organized underwent significant remodeling. Morphological remodeling and changes in dynamic activity at the subcellular level are essential to maintain heart function after infarction in a heart disease model.
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Affiliation(s)
- Chiung Wen Kuo
- Research Center for Applied Science, Academia Sinica, Taipei, Taiwan
| | | | - Yen-Ting Liu
- Research Center for Applied Science, Academia Sinica, Taipei, Taiwan
| | - Di-Yen Chueh
- Research Center for Applied Science, Academia Sinica, Taipei, Taiwan
| | - Peilin Chen
- Research Center for Applied Science, Academia Sinica, Taipei, Taiwan
- Institute of Physics, Academia Sinica, Taipei, Taiwan
- *Correspondence: Peilin Chen,
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30
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Misumi Y, Ando Y, Ueda M. Early transverse tubule involvement in cardiomyocytes in hereditary transthyretin amyloidosis; A possible cause of cardiac events. Cardiovasc Pathol 2022; 61:107458. [PMID: 35872346 DOI: 10.1016/j.carpath.2022.107458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 07/17/2022] [Accepted: 07/17/2022] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Cardiac involvement is one of the most frequent and fatal manifestations of hereditary transthyretin (ATTRv) amyloidosis. This study sought to clarify the pathogenesis of ATTRv amyloidosis, specifically, how transthyretin (TTR) amyloid begins to deposit in cardiomyocytes and how this deposition progresses in these cells. METHODS We analyzed autopsy cardiac tissues from five patients with ATTRv amyloidosis by using confocal microscopy with thioflavin S staining and immunofluorescence and electron microscopy to demonstrate the pattern of TTR amyloid deposition in cardiomyocytes. RESULTS We demonstrated predominant amyloid deposition in the transverse tubules (t-tubules) of cardiomyocytes at the early stage of TTR amyloid deposition. Also, a pattern of the progression of amyloid deposition from deeply invaginated extracellular matrix, i.e. t-tubules, to cell surface extracellular matrix, i.e. basement membrane, was noted. Three-dimensional confocal microscopic images revealed the abnormal architecture of the t-tubules with nodular swelling, branching, and confluence in the cardiomyocytes with amyloid deposition. Double immunofluorescence staining with anti-TTR antibody and CACNA1C antibody demonstrated reduced voltage-dependent calcium channels around amyloid deposition. CONCLUSIONS Our pathological study demonstrated that t-tubule involvement is an early event in cardiomyocytes in the pathogenesis of ATTRv amyloidosis. This finding may indicate that disruption of t-tubules in cardiomyocytes may contribute to the pathogenesis of cardiac events including heart failure and arrhythmia.
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Affiliation(s)
- Yohei Misumi
- Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
| | - Yukio Ando
- Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan; Department of Amyloidosis Research, Nagasaki International University, Nagasaki, Japan
| | - Mitsuharu Ueda
- Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
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31
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Weninger G, Pochechueva T, El Chami D, Luo X, Kohl T, Brandenburg S, Urlaub H, Guan K, Lenz C, Lehnart SE. Calpain cleavage of Junctophilin-2 generates a spectrum of calcium-dependent cleavage products and DNA-rich NT 1-fragment domains in cardiomyocytes. Sci Rep 2022; 12:10387. [PMID: 35725601 PMCID: PMC9209451 DOI: 10.1038/s41598-022-14320-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 06/06/2022] [Indexed: 11/16/2022] Open
Abstract
Calpains are calcium-activated neutral proteases involved in the regulation of key signaling pathways. Junctophilin-2 (JP2) is a Calpain-specific proteolytic target and essential structural protein inside Ca2+ release units required for excitation-contraction coupling in cardiomyocytes. While downregulation of JP2 by Calpain cleavage in heart failure has been reported, the precise molecular identity of the Calpain cleavage sites and the (patho-)physiological roles of the JP2 proteolytic products remain controversial. We systematically analyzed the JP2 cleavage fragments as function of Calpain-1 versus Calpain-2 proteolytic activities, revealing that both Calpain isoforms preferentially cleave mouse JP2 at R565, but subsequently at three additional secondary Calpain cleavage sites. Moreover, we identified the Calpain-specific primary cleavage products for the first time in human iPSC-derived cardiomyocytes. Knockout of RyR2 in hiPSC-cardiomyocytes destabilized JP2 resulting in an increase of the Calpain-specific cleavage fragments. The primary N-terminal cleavage product NT1 accumulated in the nucleus of mouse and human cardiomyocytes in a Ca2+-dependent manner, closely associated with euchromatic chromosomal regions, where NT1 is proposed to function as a cardio-protective transcriptional regulator in heart failure. Taken together, our data suggest that stabilizing NT1 by preventing secondary cleavage events by Calpain and other proteases could be an important therapeutic target for future studies.
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Affiliation(s)
- Gunnar Weninger
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Str. 42a, 37075, Göttingen, Germany.,Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075, Göttingen, Germany.,Collaborative Research Center SFB1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, 37073, Göttingen, Germany.,Department of Physiology and Cellular Biophysics, Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, 10032, USA
| | - Tatiana Pochechueva
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Str. 42a, 37075, Göttingen, Germany.,Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075, Göttingen, Germany.,Collaborative Research Center SFB1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, 37073, Göttingen, Germany
| | - Dana El Chami
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Str. 42a, 37075, Göttingen, Germany.,Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075, Göttingen, Germany.,Collaborative Research Center SFB1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, 37073, Göttingen, Germany
| | - Xiaojing Luo
- Institute of Pharmacology and Toxicology, Technische Universität Dresden, 01307, Dresden, Germany
| | - Tobias Kohl
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Str. 42a, 37075, Göttingen, Germany.,Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075, Göttingen, Germany.,Collaborative Research Center SFB1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, 37073, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC2067), University of Göttingen, 37073, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site, 37075, Göttingen, Germany
| | - Sören Brandenburg
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Str. 42a, 37075, Göttingen, Germany.,Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075, Göttingen, Germany.,Collaborative Research Center SFB1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, 37073, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC2067), University of Göttingen, 37073, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site, 37075, Göttingen, Germany
| | - Henning Urlaub
- Collaborative Research Center SFB1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, 37073, Göttingen, Germany.,Proteomanalyse, Department of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.,Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
| | - Kaomei Guan
- Institute of Pharmacology and Toxicology, Technische Universität Dresden, 01307, Dresden, Germany
| | - Christof Lenz
- Proteomanalyse, Department of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany. .,Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany.
| | - Stephan E Lehnart
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Str. 42a, 37075, Göttingen, Germany. .,Department of Cardiology and Pneumology, University Medical Center Göttingen, 37075, Göttingen, Germany. .,Collaborative Research Center SFB1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, 37073, Göttingen, Germany. .,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC2067), University of Göttingen, 37073, Göttingen, Germany. .,DZHK (German Centre for Cardiovascular Research), partner site, 37075, Göttingen, Germany.
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32
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Wang J, Shi Q, Wang Y, Dawson LW, Ciampa G, Zhao W, Zhang G, Chen B, Weiss RM, Grueter CE, Hall DD, Song LS. Gene Therapy With the N-Terminus of Junctophilin-2 Improves Heart Failure in Mice. Circ Res 2022; 130:1306-1317. [PMID: 35317607 PMCID: PMC9050933 DOI: 10.1161/circresaha.121.320680] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Transcriptional remodeling is known to contribute to heart failure (HF). Targeting stress-dependent gene expression mechanisms may represent a clinically relevant gene therapy option. We recently uncovered a salutary mechanism in the heart whereby JP2 (junctophilin-2), an essential component of the excitation-contraction coupling apparatus, is site-specifically cleaved and releases an N-terminal fragment (JP2NT [N-terminal fragment of JP2]) that translocates into the nucleus and functions as a transcriptional repressor of HF-related genes. This study aims to determine whether JP2NT can be leveraged by gene therapy techniques for attenuating HF progression in a preclinical pressure overload model. METHODS We intraventricularly injected adeno-associated virus (AAV) (2/9) vectors expressing eGFP (enhanced green fluorescent protein), JP2NT, or DNA-binding deficient JP2NT (JP2NTΔbNLS/ARR) into neonatal mice and induced cardiac stress by transaortic constriction (TAC) 9 weeks later. We also treated mice with established moderate HF from TAC stress with either AAV-JP2NT or AAV-eGFP. RNA-sequencing analysis was used to reveal changes in hypertrophic and HF-related gene transcription by JP2NT gene therapy after TAC. Echocardiography, confocal imaging, and histology were performed to evaluate heart function and pathological myocardial remodeling following stress. RESULTS Mice preinjected with AAV-JP2NT exhibited ameliorated cardiac remodeling following TAC. The JP2NT DNA-binding domain is required for cardioprotection as its deletion within the AAV-JP2NT vector prevented improvement in TAC-induced cardiac dysfunction. Functional and histological data suggest that JP2NT gene therapy after the onset of cardiac dysfunction is effective at slowing the progression of HF. RNA-sequencing analysis further revealed a broad reversal of hypertrophic and HF-related gene transcription by JP2NT overexpression after TAC. CONCLUSIONS Our prevention- and intervention-based approaches here demonstrated that AAV-mediated delivery of JP2NT into the myocardium can attenuate stress-induced transcriptional remodeling and the development of HF when administered either before or after cardiac stress initiation. Our data indicate that JP2NT gene therapy holds great potential as a novel therapeutic for treating hypertrophy and HF.
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Affiliation(s)
- Jinxi Wang
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA 52242
| | - Qian Shi
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA 52242
| | - Yihui Wang
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA 52242
| | - Logan W. Dawson
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242
| | - Grace Ciampa
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242
| | - Weiyang Zhao
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA 52242
| | - Guangqin Zhang
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA 52242
| | - Biyi Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA 52242
| | - Robert M. Weiss
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA 52242
| | - Chad E. Grueter
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA 52242
| | - Duane D. Hall
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA 52242
| | - Long-Sheng Song
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA 52242
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242
- Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
- Department of Veterans Affairs, Iowa City Medical Center, IA 52242
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33
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Lu F, Ma Q, Xie W, Liou CL, Zhang D, Sweat ME, Jardin BD, Naya FJ, Guo Y, Cheng H, Pu WT. CMYA5 establishes cardiac dyad architecture and positioning. Nat Commun 2022; 13:2185. [PMID: 35449169 PMCID: PMC9023524 DOI: 10.1038/s41467-022-29902-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 04/05/2022] [Indexed: 11/18/2022] Open
Abstract
Cardiac excitation-contraction coupling requires dyads, the nanoscopic microdomains formed adjacent to Z-lines by apposition of transverse tubules and junctional sarcoplasmic reticulum. Disruption of dyad architecture and function are common features of diseased cardiomyocytes. However, little is known about the mechanisms that modulate dyad organization during cardiac development, homeostasis, and disease. Here, we use proximity proteomics in intact, living hearts to identify proteins enriched near dyads. Among these proteins is CMYA5, an under-studied striated muscle protein that co-localizes with Z-lines, junctional sarcoplasmic reticulum proteins, and transverse tubules in mature cardiomyocytes. During cardiac development, CMYA5 positioning adjacent to Z-lines precedes junctional sarcoplasmic reticulum positioning or transverse tubule formation. CMYA5 ablation disrupts dyad architecture, dyad positioning at Z-lines, and junctional sarcoplasmic reticulum Ca2+ release, leading to cardiac dysfunction and inability to tolerate pressure overload. These data provide mechanistic insights into cardiomyopathy pathogenesis by demonstrating that CMYA5 anchors junctional sarcoplasmic reticulum to Z-lines, establishes dyad architecture, and regulates dyad Ca2+ release.
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Affiliation(s)
- Fujian Lu
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Qing Ma
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - 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, 710049, Xi'an, Shanxi, China
| | - Carter L Liou
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Donghui Zhang
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Science, Hubei University, 430062, Wuhan, Hubei, China
| | - Mason E Sweat
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Blake D Jardin
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Francisco J Naya
- Department of Biology, Program in Cell and Molecular Biology, Boston University, Boston, MA, 02215, USA
| | - Yuxuan Guo
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
- Peking University Health Science Center, School of Basic Medical Sciences, The Institute of Cardiovascular Sciences, Key Laboratory of Molecular Cardiovascular Science of Ministry of Education, 100191, Beijing, China
| | - Heping Cheng
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China
| | - William T Pu
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.
- Harvard Stem Cell Institute, 7 Divinity Avenue, Cambridge, MA, 02138, USA.
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Prasad V, Makkaoui N, Rajan R, Patel A, Mainali B, Bagchi P, Kumar R, Rogers J, Diamond J, Maxwell JT. Loss of cardiac myosin light chain kinase contributes to contractile dysfunction in right ventricular pressure overload. Physiol Rep 2022; 10:e15238. [PMID: 35384363 PMCID: PMC8981447 DOI: 10.14814/phy2.15238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 03/03/2022] [Accepted: 03/06/2022] [Indexed: 06/14/2023] Open
Abstract
Nearly 1 in every 100 children born have a congenital heart defect. Many of these defects primarily affect the right heart causing pressure overload of the right ventricle (RV). The RV maintains function by adapting to the increased pressure; however, many of these adaptations eventually lead to RV hypertrophy and failure. In this study, we aim to identify the cellular and molecular mechanisms of these adaptions. We utilized a surgical animal model of pulmonary artery banding (PAB) in juvenile rats that has been shown to accurately recapitulate the physiology of right ventricular pressure overload in young hearts. Using this model, we examined changes in cardiac myocyte protein expression as a result of pressure overload with mass spectrometry 4 weeks post-banding. We found pressure overload of the RV induced significant downregulation of cardiac myosin light chain kinase (cMLCK). Single myocyte calcium and contractility recordings showed impaired contraction and relaxation in PAB RV myocytes, consistent with the loss of cMLCK. In the PAB myocytes, calcium transients were of smaller amplitude and decayed at a slower rate compared to controls. We also identified miR-200c, which has been shown to regulate cMLCK expression, as upregulated in the RV in response to pressure overload. These results indicate the loss of cMLCK is a critical maladaptation of the RV to pressure overload and represents a novel target for therapeutic approaches to treat RV hypertrophy and failure associated with congenital heart defects.
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Affiliation(s)
- Vidhya Prasad
- Division of Pediatric CardiologyDepartment of PediatricsEmory University School of MedicineAtlantaGeorgiaUSA
- Children’s Heart Research & Outcomes (HeRO) CenterChildren’s Healthcare of Atlanta & Emory UniversityAtlantaGeorgiaUSA
| | - Nour Makkaoui
- Division of Pediatric CardiologyDepartment of PediatricsEmory University School of MedicineAtlantaGeorgiaUSA
- Children’s Heart Research & Outcomes (HeRO) CenterChildren’s Healthcare of Atlanta & Emory UniversityAtlantaGeorgiaUSA
| | - Rohan Rajan
- Emory University College of Arts and SciencesAtlantaGeorgiaUSA
| | - Alisha Patel
- Emory University College of Arts and SciencesAtlantaGeorgiaUSA
| | - Bipul Mainali
- Emory University College of Arts and SciencesAtlantaGeorgiaUSA
| | - Pritha Bagchi
- Department of BiochemistryEmory University School of MedicineAtlantaGeorgiaUSA
| | - Rhea Kumar
- Emory University College of Arts and SciencesAtlantaGeorgiaUSA
| | - Julia Rogers
- Emory University College of Arts and SciencesAtlantaGeorgiaUSA
| | - Jake Diamond
- Emory University College of Arts and SciencesAtlantaGeorgiaUSA
| | - Joshua T. Maxwell
- Division of Pediatric CardiologyDepartment of PediatricsEmory University School of MedicineAtlantaGeorgiaUSA
- Children’s Heart Research & Outcomes (HeRO) CenterChildren’s Healthcare of Atlanta & Emory UniversityAtlantaGeorgiaUSA
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35
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Abstract
In mammalian cardiac myocytes, the plasma membrane includes the surface sarcolemma but also a network of membrane invaginations called transverse (t-) tubules. These structures carry the action potential deep into the cell interior, allowing efficient triggering of Ca2+ release and initiation of contraction. Once thought to serve as rather static enablers of excitation-contraction coupling, recent work has provided a newfound appreciation of the plasticity of the t-tubule network's structure and function. Indeed, t-tubules are now understood to support dynamic regulation of the heartbeat across a range of timescales, during all stages of life, in both health and disease. This review article aims to summarize these concepts, with consideration given to emerging t-tubule regulators and their targeting in future therapies.
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Affiliation(s)
- Katharine M Dibb
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom;
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo Norway
| | - Andrew W Trafford
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom;
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36
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Kaplan A, Amin G, Abidi E, Altara R, Booz GW, Zouein FA. Role of ranolazine in heart failure: From cellular to clinic perspective. Eur J Pharmacol 2022;:174787. [PMID: 35114190 DOI: 10.1016/j.ejphar.2022.174787] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 12/25/2021] [Accepted: 01/25/2022] [Indexed: 12/17/2022]
Abstract
Ranolazine was approved by the US Food and Drug Administration as an antianginal drug in 2006, and has been used since in certain groups of patients with stable angina. The therapeutic action of ranolazine was initially attributed to inhibitory effects on fatty acids metabolism. As investigations went on, however, it developed that the main beneficial effects of ranolazine arise from its action on the late sodium current in the heart. Since late sodium currents were discovered to be involved in various heart pathologies such as ischemia, arrhythmias, systolic and diastolic dysfunctions, and all these conditions are associated with heart failure, ranolazine has in some way been tested either directly or indirectly on heart failure in numerous experimental and clinical studies. As the heart continuously remodels following any sort of severe injury, the inhibition by ranolazine of the underlying mechanisms of cardiac remodeling including ion disturbances, oxidative stress, inflammation, apoptosis, fibrosis, metabolic dysregulation, and neurohormonal impairment are discussed, along with unresolved issues. A projection of pathologies targeted by ranolazine from cellular level to clinical is provided in this review.
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Abstract
The architectural specializations and targeted delivery pathways of cardiomyocytes ensure that L-type Ca2+ channels (CaV1.2) are concentrated on the t-tubule sarcolemma within nanometers of their intracellular partners the type 2 ryanodine receptors (RyR2) which cluster on the junctional sarcoplasmic reticulum (jSR). The organization and distribution of these two groups of cardiac calcium channel clusters critically underlies the uniform contraction of the myocardium. Ca2+ signaling between these two sets of adjacent clusters produces Ca2+ sparks that in health, cannot escalate into Ca2+ waves because there is sufficient separation of adjacent clusters so that the release of Ca2+ from one RyR2 cluster or supercluster, cannot activate and sustain the release of Ca2+ from neighboring clusters. Instead, thousands of these Ca2+ release units (CRUs) generate near simultaneous Ca2+ sparks across every cardiomyocyte during the action potential when calcium induced calcium release from RyR2 is stimulated by depolarization induced Ca2+ influx through voltage dependent CaV1.2 channel clusters. These sparks summate to generate a global Ca2+ transient that activates the myofilaments and thus the electrical signal of the action potential is transduced into a functional output, myocardial contraction. To generate more, or less contractile force to match the hemodynamic and metabolic demands of the body, the heart responds to β-adrenergic signaling by altering activity of calcium channels to tune excitation-contraction coupling accordingly. Recent accumulating evidence suggests that this tuning process also involves altered expression, and dynamic reorganization of CaV1.2 and RyR2 channels on their respective membranes to control the amplitude of Ca2+ entry, SR Ca2+ release and myocardial function. In heart failure and aging, altered distribution and reorganization of these key Ca2+ signaling proteins occurs alongside architectural remodeling and is thought to contribute to impaired contractile function. In the present review we discuss these latest developments, their implications, and future questions to be addressed.
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Affiliation(s)
- Rose E Dixon
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, CA, United States
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38
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Li C, Zheng Y, Liu Y, Jin GH, Pan H, Yin F, Wu J. The interaction protein of SORBS2 in myocardial tissue to find out the pathogenic mechanism of LVNC disease. Aging (Albany NY) 2022; 14:800-810. [PMID: 35050860 PMCID: PMC8833133 DOI: 10.18632/aging.203841] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 12/08/2021] [Indexed: 11/25/2022]
Abstract
BACKGROUND Left ventricular noncompaction cardiomyopathy (LVNC) is a cardiac disorder characterized by an excessive trabecular meshwork of deep intertrabecular recesses within the ventricular myocardium. Sorbin and SH3 domain-containing protein 2 (SORBS2) converges on the actin and microtubule cytoskeleton. Here, we investigated the proteins interacting with SORBS2 to elucidate the pathogenic mechanism of LVNC. As reported in previous studies, SORBS2 enhances the occurrence of LVNC by potentiating heart failure, but the specific mechanism remains unclear. METHODS Building from our previous finding of elevated SORBS2 levels in LVNC hearts, we screened for proteins interacting with SORBS2 by proteomics and conducting IP experiments. Co-IP and immunofluorescence were used to verify the effects. RESULTS We selected several proteins with high scores and high coverage that could be closely related to SORBS2 according to earlier reports showing a correlation with LVNC for verification. We finally obtained several proteins that were related to the pathogenesis of LVNC and also interacted with SORBS2, such as α-actinin, β-tubulin, MYH7, FLNA, MYBPC3, YWHAQ and DES, and YWHAQ was the most associated. CONCLUSIONS We focused on the YWHAQ protein, and we identified a novel mechanism through which SORBS2 interacts with YWHAQ, having a negative effect on the cell cycle, potentially leading to LVNC.
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Affiliation(s)
- Chunyan Li
- Department of Clinical Laboratory, Beijing Jishuitan Hospital, Beijing 100035, China
| | - Yang Zheng
- Department of Orthopaedics, Fourth Medical Center of PLA General Hospital, People's Republic of China, National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, Beijing 10048, China
| | - Ying Liu
- Department of Clinical Laboratory, Beijing Jishuitan Hospital, Beijing 100035, China
| | - Guo Hong Jin
- Department of Clinical Laboratory, Beijing Jishuitan Hospital, Beijing 100035, China
| | - Haizhou Pan
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhejiang University, Hangzhou 310014, China
| | - Fenghui Yin
- The Third People's Hospital of Chengdu, Chengdu 610031, China
| | - Jun Wu
- Department of Clinical Laboratory, Beijing Jishuitan Hospital, Beijing 100035, China.,Department of Laboratory Medicine, Peking University Fourth School of Clinical Medicine, Beijing Jishuitan Hospital, Xicheng, Beijing 100035, China
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Hakui H, Kioka H, Miyashita Y, Nishimura S, Matsuoka K, Kato H, Tsukamoto O, Kuramoto Y, Takuwa A, Takahashi Y, Saito S, Ohta K, Asanuma H, Fu HY, Shinomiya H, Yamada N, Ohtani T, Sawa Y, Kitakaze M, Takashima S, Sakata Y, Asano Y. Loss-of-function mutations in the co-chaperone protein BAG5 cause dilated cardiomyopathy requiring heart transplantation. Sci Transl Med 2022; 14:eabf3274. [PMID: 35044787 DOI: 10.1126/scitranslmed.abf3274] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Dilated cardiomyopathy (DCM) is a major cause of heart failure, characterized by ventricular dilatation and systolic dysfunction. Familial DCM is reportedly caused by mutations in more than 50 genes, requiring precise disease stratification based on genetic information. However, the underlying genetic causes of 60 to 80% of familial DCM cases remain unknown. Here, we identified that homozygous truncating mutations in the gene encoding Bcl-2-associated athanogene (BAG) co-chaperone 5 (BAG5) caused inherited DCM in five patients among four unrelated families with complete penetrance. BAG5 acts as a nucleotide exchange factor for heat shock cognate 71 kDa protein (HSC70), promoting adenosine diphosphate release and activating HSC70-mediated protein folding. Bag5 mutant knock-in mice exhibited ventricular dilatation, arrhythmogenicity, and poor prognosis under catecholamine stimulation, recapitulating the human DCM phenotype, and administration of an adeno-associated virus 9 vector carrying the wild-type BAG5 gene could fully ameliorate these DCM phenotypes. Immunocytochemical analysis revealed that BAG5 localized to junctional membrane complexes (JMCs), critical microdomains for calcium handling. Bag5-mutant mouse cardiomyocytes exhibited decreased abundance of functional JMC proteins under catecholamine stimulation, disrupted JMC structure, and calcium handling abnormalities. We also identified heterozygous truncating mutations in three patients with tachycardia-induced cardiomyopathy, a reversible DCM subtype associated with abnormal calcium homeostasis. Our study suggests that loss-of-function mutations in BAG5 can cause DCM, that BAG5 may be a target for genetic testing in cases of DCM, and that gene therapy may potentially be a treatment for this disease.
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Affiliation(s)
- Hideyuki Hakui
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Hidetaka Kioka
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Yohei Miyashita
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Shunsuke Nishimura
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Ken Matsuoka
- Department of Medical Biochemistry, Osaka University Graduate School of Frontier Biosciences, Suita, Osaka 565-0871, Japan
| | - Hisakazu Kato
- Department of Medical Biochemistry, Osaka University Graduate School of Frontier Biosciences, Suita, Osaka 565-0871, Japan
| | - Osamu Tsukamoto
- Department of Medical Biochemistry, Osaka University Graduate School of Frontier Biosciences, Suita, Osaka 565-0871, Japan
| | - Yuki Kuramoto
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Ayako Takuwa
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Yusuke Takahashi
- Department of Molecular Pharmacology, National Cerebral and Cardiovascular Center, Suita, Osaka 564-8565, Japan
| | - Shigeyoshi Saito
- Department of Medical Physics and Engineering, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan.,Department of Biomedical Imaging, National Cerebral and Cardiovascular Center, Suita, Osaka 564-8565, Japan
| | - Kunio Ohta
- Department of Pediatrics, School of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa 920-8640, Japan
| | - Hiroshi Asanuma
- Department of Internal Medicine, Meiji University of Integrative Medicine, Nantan, Kyoto 629-0392, Japan
| | - Hai Ying Fu
- Department of Clinical Medicine and Development, National Cerebral and Cardiovascular Center, Suita, Osaka 564-8565, Japan
| | - Haruki Shinomiya
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Noriaki Yamada
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Tomohito Ohtani
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Yoshiki Sawa
- Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Masafumi Kitakaze
- Department of Clinical Medicine and Development, National Cerebral and Cardiovascular Center, Suita, Osaka 564-8565, Japan
| | - Seiji Takashima
- Department of Medical Biochemistry, Osaka University Graduate School of Frontier Biosciences, Suita, Osaka 565-0871, Japan
| | - Yasushi Sakata
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Yoshihiro Asano
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
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40
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Zhou J, Singh N, Monnier C, Marszalec W, Gao L, Jin J, Frisk M, Louch WE, Verma S, Krishnamurthy P, Nico E, Mulla M, Aistrup GL, Kishore R, Wasserstrom JA. Phosphatidylinositol-4,5-Bisphosphate Binding to Amphiphysin-II Modulates T-Tubule Remodeling: Implications for Heart Failure. Front Physiol 2022; 12:782767. [PMID: 35002765 PMCID: PMC8733645 DOI: 10.3389/fphys.2021.782767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/19/2021] [Indexed: 11/13/2022] Open
Abstract
BIN1 (amphyphysin-II) is a structural protein involved in T-tubule (TT) formation and phosphatidylinositol-4,5-bisphosphate (PIP2) is responsible for localization of BIN1 to sarcolemma. The goal of this study was to determine if PIP2-mediated targeting of BIN1 to sarcolemma is compromised during the development of heart failure (HF) and is responsible for TT remodeling. Immunohistochemistry showed co-localization of BIN1, Cav1.2, PIP2, and phospholipase-Cβ1 (PLCβ1) in TTs in normal rat and human ventricular myocytes. PIP2 levels were reduced in spontaneously hypertensive rats during HF progression compared to age-matched controls. A PIP Strip assay of two native mouse cardiac-specific isoforms of BIN1 including the longest (cardiac BIN1 #4) and shortest (cardiac BIN1 #1) isoforms as well human skeletal BIN1 showed that all bound PIP2. In addition, overexpression of all three BIN1 isoforms caused tubule formation in HL-1 cells. A triple-lysine motif in a short loop segment between two helices was mutated and replaced by negative charges which abolished tubule formation, suggesting a possible location for PIP2 interaction aside from known consensus binding sites. Pharmacological PIP2 depletion in rat ventricular myocytes caused TT loss and was associated with changes in Ca2+ release typically found in myocytes during HF, including a higher variability in release along the cell length and a slowing in rise time, time to peak, and decay time in treated myocytes. These results demonstrate that depletion of PIP2 can lead to TT disruption and suggest that PIP2 interaction with cardiac BIN1 is required for TT maintenance and function.
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Affiliation(s)
- Junlan Zhou
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Neha Singh
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Chloe Monnier
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - William Marszalec
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Li Gao
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Jing Jin
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Michael Frisk
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital, Oslo, Norway.,K. G. Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research (IEMR), Oslo University Hospital, Oslo, Norway.,K. G. Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Suresh Verma
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Prasanna Krishnamurthy
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Elsa Nico
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Maaz Mulla
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Gary L Aistrup
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Raj Kishore
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - J Andrew Wasserstrom
- Department of Medicine (Cardiology), Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
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41
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Abstract
Junctophilins (JPHs) comprise a family of structural proteins that connect the plasma membrane to intracellular organelles such as the endo/sarcoplasmic reticulum. Tethering of these membrane structures results in the formation of highly organized subcellular junctions that play important signaling roles in all excitable cell types. There are four JPH isoforms, expressed primarily in muscle and neuronal cell types. Each JPH protein consists of 6 'membrane occupation and recognition nexus' (MORN) motifs, a joining region connecting these to another set of 2 MORN motifs, a putative alpha-helical region, a divergent region exhibiting low homology between JPH isoforms, and a carboxy-terminal transmembrane region anchoring into the ER/SR membrane. JPH isoforms play essential roles in developing and maintaining subcellular membrane junctions. Conversely, inherited mutations in JPH2 cause hypertrophic or dilated cardiomyopathy, while trinucleotide expansions in the JPH3 gene cause Huntington Disease-Like 2. Loss of JPH1 protein levels can cause skeletal myopathy, while loss of cardiac JPH2 levels causes heart failure and atrial fibrillation, among other disease. This review will provide a comprehensive overview of the JPH gene family, phylogeny, and evolutionary analysis of JPH genes and other MORN domain proteins. JPH biogenesis, membrane tethering, and binding partners will be discussed, as well as functional roles of JPH isoforms in excitable cells. Finally, potential roles of JPH isoform deficits in human disease pathogenesis will be reviewed.
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Affiliation(s)
- Stephan E Lehnart
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Department of Cardiology and Pneumology, Georg-August University Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas, United States; Departments of Molecular Physiology and Biophysics, Medicine (Cardiology), Pediatrics (Cardiology), Neuroscience, and Center for Space Medicine, Baylor College of Medicine, Houston, Texas, United States
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42
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Hoang-Trong TM, Ullah A, Lederer WJ, Jafri MS. A Stochastic Spatiotemporal Model of Rat Ventricular Myocyte Calcium Dynamics Demonstrated Necessary Features for Calcium Wave Propagation. Membranes (Basel) 2021; 11:989. [PMID: 34940490 PMCID: PMC8706945 DOI: 10.3390/membranes11120989] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/12/2021] [Accepted: 12/15/2021] [Indexed: 11/16/2022]
Abstract
Calcium (Ca2+) plays a central role in the excitation and contraction of cardiac myocytes. Experiments have indicated that calcium release is stochastic and regulated locally suggesting the possibility of spatially heterogeneous calcium levels in the cells. This spatial heterogeneity might be important in mediating different signaling pathways. During more than 50 years of computational cell biology, the computational models have been advanced to incorporate more ionic currents, going from deterministic models to stochastic models. While periodic increases in cytoplasmic Ca2+ concentration drive cardiac contraction, aberrant Ca2+ release can underly cardiac arrhythmia. However, the study of the spatial role of calcium ions has been limited due to the computational expense of using a three-dimensional stochastic computational model. In this paper, we introduce a three-dimensional stochastic computational model for rat ventricular myocytes at the whole-cell level that incorporate detailed calcium dynamics, with (1) non-uniform release site placement, (2) non-uniform membrane ionic currents and membrane buffers, (3) stochastic calcium-leak dynamics and (4) non-junctional or rogue ryanodine receptors. The model simulates spark-induced spark activation and spark-induced Ca2+ wave initiation and propagation that occur under conditions of calcium overload at the closed-cell condition, but not when Ca2+ levels are normal. This is considered important since the presence of Ca2+ waves contribute to the activation of arrhythmogenic currents.
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Affiliation(s)
- Tuan Minh Hoang-Trong
- School of Systems Biology, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA 22030, USA; (T.M.H.-T.); (A.U.)
| | - Aman Ullah
- School of Systems Biology, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA 22030, USA; (T.M.H.-T.); (A.U.)
| | - William Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Mohsin Saleet Jafri
- School of Systems Biology, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA 22030, USA; (T.M.H.-T.); (A.U.)
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
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43
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Howe K, Ross JM, Loiselle DS, Han JC, Crossman DJ. Right-sided heart failure is also associated with transverse tubule remodeling in the left ventricle. Am J Physiol Heart Circ Physiol 2021; 321:H940-H947. [PMID: 34559582 DOI: 10.1152/ajpheart.00298.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/22/2021] [Indexed: 11/22/2022]
Abstract
Right-sided heart failure is a common consequence of pulmonary arterial hypertension. Overloading the right ventricle results in right ventricular hypertrophy, which progresses to failure in a process characterized by impaired Ca2+ dynamics and force production that is linked with transverse (t)-tubule remodeling. This also unloads the left ventricle, which consequently atrophies. Experimental left-ventricular unloading can result in t-tubule remodeling, but it is currently unclear if this occurs in right-sided heart failure. In this work, we used a model of monocrotaline (MCT)-induced right heart failure in male rats, using confocal microscopy to investigate cellular remodeling of t-tubules, junctophilin-2 (JPH2), and ryanodine receptor-2 (RyR2). We examined remodeling across tissue anatomical regions of both ventricles: in trabeculae, papillary muscles, and free walls. Our analyses revealed that MCT hearts demonstrated a significant loss of t-tubule periodicity, disruption of the normal sarcomere striated pattern with JPH2 labeling, and also a disorganized striated pattern of RyR2, a feature not previously reported in right heart failure. Remodeling of JPH2 and RyR2 in the MCT heart was more pronounced in papillary muscles and trabeculae compared with free walls, particularly in the left ventricle. We find that these structures, commonly used as ex vivo muscle preparations, are more sensitive to the disease process.NEW & NOTEWORTHY In this work, we demonstrate that t-tubule remodeling occurs in the atrophied left ventricle as well as the overloaded right ventricle after right-side heart failure. Moreover, we identify that t-tubule remodeling in both ventricles is linked to sarcoplasmic reticulum remodeling as indicated by decreased labeling periodicity of both the Ca2+ release channel, RyR2, and the cardiac junction-forming protein, JPH2, that forms a link between the sarcoplasmic reticulum and sarcolemma. Studies developing treatments for right-sided heart failure should consider effects on both the right and left ventricle.
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MESH Headings
- Animals
- Calcium Signaling
- Disease Models, Animal
- Heart Failure/chemically induced
- Heart Failure/metabolism
- Heart Failure/pathology
- Heart Failure/physiopathology
- Heart Ventricles/metabolism
- Heart Ventricles/pathology
- Heart Ventricles/physiopathology
- Hypertrophy, Left Ventricular/chemically induced
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/pathology
- Hypertrophy, Left Ventricular/physiopathology
- Hypertrophy, Right Ventricular/chemically induced
- Hypertrophy, Right Ventricular/metabolism
- Hypertrophy, Right Ventricular/pathology
- Hypertrophy, Right Ventricular/physiopathology
- Male
- Membrane Proteins/metabolism
- Monocrotaline
- Rats, Wistar
- Ryanodine Receptor Calcium Release Channel/metabolism
- Sarcomeres/metabolism
- Sarcomeres/pathology
- Ventricular Function, Left
- Ventricular Function, Right
- Ventricular Remodeling
- Rats
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Affiliation(s)
- Kevin Howe
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Jacqueline M Ross
- Biomedical Imaging Research Unit, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Denis S Loiselle
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - June-Chiew Han
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - David J Crossman
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
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Hou Y, Bai J, Shen X, de Langen O, Li A, Lal S, Dos Remedios CG, Baddeley D, Ruygrok PN, Soeller C, Crossman DJ. Nanoscale Organisation of Ryanodine Receptors and Junctophilin-2 in the Failing Human Heart. Front Physiol 2021; 12:724372. [PMID: 34690801 PMCID: PMC8531480 DOI: 10.3389/fphys.2021.724372] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Accepted: 09/03/2021] [Indexed: 11/16/2022] Open
Abstract
The disrupted organisation of the ryanodine receptors (RyR) and junctophilin (JPH) is thought to underpin the transverse tubule (t-tubule) remodelling in a failing heart. Here, we assessed the nanoscale organisation of these two key proteins in the failing human heart. Recently, an advanced feature of the t-tubule remodelling identified large flattened t-tubules called t-sheets, that were several microns wide. Previously, we reported that in the failing heart, the dilated t-tubules up to ~1 μm wide had increased collagen, and we hypothesised that the t-sheets would also be associated with collagen deposits. Direct stochastic optical reconstruction microscopy (dSTORM), confocal microscopy, and western blotting were used to evaluate the cellular distribution of excitation-contraction structures in the cardiac myocytes from patients with idiopathic dilated cardiomyopathy (IDCM) compared to myocytes from the non-failing (NF) human heart. The dSTORM imaging of RyR and JPH found no difference in the colocalisation between IDCM and NF myocytes, but there was a higher colocalisation at the t-tubule and sarcolemma compared to the corbular regions. Western blots revealed no change in the JPH expression but did identify a ~50% downregulation of RyR (p = 0.02). The dSTORM imaging revealed a trend for the smaller t-tubular RyR clusters (~24%) and reduced the t-tubular RyR cluster density (~35%) that resulted in a 50% reduction of t-tubular RyR tetramers in the IDCM myocytes (p < 0.01). Confocal microscopy identified the t-sheets in all the IDCM hearts examined and found that they are associated with the reticular collagen fibres within the lumen. However, the size and density of the RyR clusters were similar in the myocyte regions associated with t-sheets and t-tubules. T-tubule remodelling is associated with a reduced RyR expression that may contribute to the reduced excitation-contraction coupling in the failing human heart.
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Affiliation(s)
- Yufeng Hou
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Jizhong Bai
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Xin Shen
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Oscar de Langen
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Amy Li
- Department of Pharmacy and Biomedical Science, Health and Engineering, La Trobe University, Bendigo, VIC, Australia
| | - Sean Lal
- Faculty of Medicine and Science, University of Sydney, Sydney, NSW, Australia
| | | | - David Baddeley
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Peter N Ruygrok
- Department of Cardiology, Auckland City Hospital, Auckland, New Zealand
| | | | - David J Crossman
- Department of Physiology, University of Auckland, Auckland, New Zealand
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Wang J, Ciampa G, Zheng D, Shi Q, Chen B, Abel ED, Peng T, Hall DD, Song LS. Calpain-2 specifically cleaves Junctophilin-2 at the same site as Calpain-1 but with less efficacy. Biochem J 2021; 478:3539-53. [PMID: 34524407 DOI: 10.1042/BCJ20210629] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/14/2021] [Accepted: 09/15/2021] [Indexed: 11/17/2022]
Abstract
Calpain proteolysis contributes to the pathogenesis of heart failure but the calpain isoforms responsible and their substrate specificities have not been rigorously defined. One substrate, Junctophilin-2 (JP2), is essential for maintaining junctional cardiac dyads and excitation-contraction coupling. We previously demonstrated that mouse JP2 is cleaved by calpain-1 (CAPN1) between Arginine 565 (R565) and Threonine 566 (T566). Recently, calpain-2 (CAPN2) was reported to cleave JP2 at a novel site between Glycine 482 (G482) and Threonine 483 (T483). We aimed to directly compare the contributions of each calpain isoform, their Ca2+ sensitivity, and their cleavage site selection for JP2. We find CAPN1, CAPN2 and their requisite CAPNS1 regulatory subunit are induced by pressure overload stress that is concurrent with JP2 cleavage. Using in vitro calpain cleavage assays, we demonstrate that CAPN1 and CAPN2 cleave JP2 into similar 75 kD N-terminal (JP2NT) and 25 kD C-terminal fragments (JP2CT) with CAPNS1 co-expression enhancing proteolysis. Deletion mutagenesis shows both CAPN1 and CAPN2 require R565/T566 but not G482/T483. When heterologously expressed, the JP2CT peptide corresponding to R565/T566 cleavage approximates the 25 kD species found during cardiac stress while the C-terminal peptide from potential cleavage at G482/T483 produces a 35 kD product. Similar results were obtained for human JP2. Finally, we show that CAPN1 has higher Ca2+ sensitivity and cleavage efficacy than CAPN2 on JP2 and other cardiac substrates including cTnT, cTnI and β2-spectrin. We conclude that CAPN2 cleaves JP2 at the same functionally conserved R565/T566 site as CAPN1 but with less efficacy and suggest heart failure may be targeted through specific inhibition of CAPN1.
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Hamilton S, Terentyeva R, Perger F, Hernández Orengo B, Martin B, Gorr MW, Belevych AE, Clements RT, Györke S, Terentyev D. MCU overexpression evokes disparate dose-dependent effects on mito-ROS and spontaneous Ca 2+ release in hypertrophic rat cardiomyocytes. Am J Physiol Heart Circ Physiol 2021; 321:H615-H632. [PMID: 34415186 PMCID: PMC8794228 DOI: 10.1152/ajpheart.00126.2021] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 08/13/2021] [Accepted: 08/13/2021] [Indexed: 12/11/2022]
Abstract
Cardiac dysfunction in heart failure (HF) and diabetic cardiomyopathy (DCM) is associated with aberrant intracellular Ca2+ handling and impaired mitochondrial function accompanied with reduced mitochondrial calcium concentration (mito-[Ca2+]). Pharmacological or genetic facilitation of mito-Ca2+ uptake was shown to restore Ca2+ transient amplitude in DCM and HF, improving contractility. However, recent reports suggest that pharmacological enhancement of mito-Ca2+ uptake can exacerbate ryanodine receptor-mediated spontaneous sarcoplasmic reticulum (SR) Ca2+ release in ventricular myocytes (VMs) from diseased animals, increasing propensity to stress-induced ventricular tachyarrhythmia. To test whether chronic recovery of mito-[Ca2+] restores systolic Ca2+ release without adverse effects in diastole, we overexpressed mitochondrial Ca2+ uniporter (MCU) in VMs from male rat hearts with hypertrophy induced by thoracic aortic banding (TAB). Measurement of mito-[Ca2+] using genetic probe mtRCamp1h revealed that mito-[Ca2+] in TAB VMs paced at 2 Hz under β-adrenergic stimulation is lower compared with shams. Adenoviral 2.5-fold MCU overexpression in TAB VMs fully restored mito-[Ca2+]. However, it failed to improve cytosolic Ca2+ handling and reduce proarrhythmic spontaneous Ca2+ waves. Furthermore, mitochondrial-targeted genetic probes MLS-HyPer7 and OMM-HyPer revealed a significant increase in emission of reactive oxygen species (ROS) in TAB VMs with 2.5-fold MCU overexpression. Conversely, 1.5-fold MCU overexpression in TABs, that led to partial restoration of mito-[Ca2+], reduced mitochondria-derived reactive oxygen species (mito-ROS) and spontaneous Ca2+ waves. Our findings emphasize the key role of elevated mito-ROS in disease-related proarrhythmic Ca2+ mishandling. These data establish nonlinear mito-[Ca2+]/mito-ROS relationship, whereby partial restoration of mito-[Ca2+] in diseased VMs is protective, whereas further enhancement of MCU-mediated Ca2+ uptake exacerbates damaging mito-ROS emission.NEW & NOTEWORTHY Defective intracellular Ca2+ homeostasis and aberrant mitochondrial function are common features in cardiac disease. Here, we directly compared potential benefits of mito-ROS scavenging and restoration of mito-Ca2+ uptake by overexpressing MCU in ventricular myocytes from hypertrophic rat hearts. Experiments using novel mito-ROS and Ca2+ biosensors demonstrated that mito-ROS scavenging rescued both cytosolic and mito-Ca2+ homeostasis, whereas moderate and high MCU overexpression demonstrated disparate effects on mito-ROS emission, with only a moderate increase in MCU being beneficial.
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MESH Headings
- Adrenergic beta-Agonists/pharmacology
- Animals
- Arrhythmias, Cardiac/genetics
- Arrhythmias, Cardiac/metabolism
- Arrhythmias, Cardiac/pathology
- Arrhythmias, Cardiac/physiopathology
- Biosensing Techniques
- Calcium/metabolism
- Calcium Channels/genetics
- Calcium Channels/metabolism
- Calcium Signaling/drug effects
- Cells, Cultured
- Disease Models, Animal
- Heart Rate
- Hypertrophy, Left Ventricular/genetics
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/pathology
- Hypertrophy, Left Ventricular/physiopathology
- Male
- Microscopy, Confocal
- Mitochondria, Heart/drug effects
- Mitochondria, Heart/genetics
- Mitochondria, Heart/metabolism
- Mitochondria, Heart/pathology
- Myocardial Contraction
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Rats, Sprague-Dawley
- Reactive Oxygen Species/metabolism
- Up-Regulation
- Ventricular Function, Left
- Ventricular Remodeling
- Rats
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Affiliation(s)
- Shanna Hamilton
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Radmila Terentyeva
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Fruzsina Perger
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Benjamín Hernández Orengo
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Benjamin Martin
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Matthew W Gorr
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
- College of Nursing, The Ohio State University, Columbus, Ohio
| | - Andriy E Belevych
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Richard T Clements
- Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island
| | - Sandor Györke
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Dmitry Terentyev
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
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Abstract
The sarcomere is the fundamental structural and functional unit of striated muscle and is directly responsible for most of its mechanical properties. The sarcomere generates active or contractile forces and determines the passive or elastic properties of striated muscle. In the heart, mutations in sarcomeric proteins are responsible for the majority of genetically inherited cardiomyopathies. Here, we review the major determinants of cardiac sarcomere mechanics including the key structural components that contribute to active and passive tension. We dissect the molecular and structural basis of active force generation, including sarcomere composition, structure, activation, and relaxation. We then explore the giant sarcomere-resident protein titin, the major contributor to cardiac passive tension. We discuss sarcomere dynamics exemplified by the regulation of titin-based stiffness and the titin life cycle. Finally, we provide an overview of therapeutic strategies that target the sarcomere to improve cardiac contraction and filling.
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Affiliation(s)
- Claudia Crocini
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Neuromuscular and Cardiovascular Cell Biology, Berlin, Germany
- German Center for Cardiovascular Research (DZHK) Partner Site Berlin, Berlin, Germany
- BioFrontiers Institute & Department of Molecular and Cellular Development, University of Colorado Boulder, Boulder, USA
| | - Michael Gotthardt
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Neuromuscular and Cardiovascular Cell Biology, Berlin, Germany
- German Center for Cardiovascular Research (DZHK) Partner Site Berlin, Berlin, Germany
- Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
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48
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Abstract
In cardiomyocytes, invaginations of the sarcolemmal membrane called t-tubules are critically important for triggering contraction by excitation-contraction (EC) coupling. These structures form functional junctions with the sarcoplasmic reticulum (SR), and thereby enable close contact between L-type Ca2+ channels (LTCCs) and Ryanodine Receptors (RyRs). This arrangement in turn ensures efficient triggering of Ca2+ release, and contraction. While new data indicate that t-tubules are capable of exhibiting compensatory remodeling, they are also widely reported to be structurally and functionally compromised during disease, resulting in disrupted Ca2+ homeostasis, impaired systolic and/or diastolic function, and arrhythmogenesis. This review summarizes these findings, while highlighting an emerging appreciation of the distinct roles of t-tubules in the pathophysiology of heart failure with reduced and preserved ejection fraction (HFrEF and HFpEF). In this context, we review current understanding of the processes underlying t-tubule growth, maintenance, and degradation, underscoring the involvement of a variety of regulatory proteins, including junctophilin-2 (JPH2), amphiphysin-2 (BIN1), caveolin-3 (Cav3), and newer candidate proteins. Upstream regulation of t-tubule structure/function by cardiac workload and specifically ventricular wall stress is also discussed, alongside perspectives for novel strategies which may therapeutically target these mechanisms.
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Affiliation(s)
- Ingunn E Setterberg
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Christopher Le
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Jia Li
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
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Tan R, Li C, Xu C, Wu Q, Gao L, Shi Y, Cui J. Targeting JP2: A New Treatment for Pulmonary Hypertension. Oxid Med Cell Longev 2021; 2021:2003446. [PMID: 34394822 DOI: 10.1155/2021/2003446] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 07/21/2021] [Accepted: 07/27/2021] [Indexed: 12/16/2022]
Abstract
Pulmonary hypertension (PH) is a disease with a complex etiology and high mortality rate. Abnormal pulmonary vasoconstriction and pulmonary vascular remodeling lead to an increase in mean pulmonary arterial blood pressure for which, and there is currently no cure. Junctophilin-2 (JP2) is beneficial for the assembly of junctional membrane complexes, the structural basis for excitation-contraction coupling that tethers the plasma membrane to the sarcoplasmic reticulum/endoplasmic reticulum and is involved in maintaining intracellular calcium concentration homeostasis and normal muscle contraction function. Recent studies have shown that JP2 maintains normal contraction and relaxation of vascular smooth muscle. In some experimental studies of drug treatments for PH, JP2 expression was increased, which improved pulmonary vascular remodeling and right ventricular function. Based on JP2 research to date, this paper summarizes the current understanding of JP2 protein structure, function, and related heart diseases and mechanisms and analyzes the feasibility and possible therapeutic strategies for targeting JP2 in PH.
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50
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Abstract
Contacts between the endoplasmic reticulum (ER) and plasma membrane (PM) contain specialized tethering proteins that bind both ER and PM membranes. In excitable cells, ER–PM contacts play an important role in calcium signaling and transferring lipids. Junctophilins are a conserved family of ER–PM tethering proteins. They are predominantly expressed in muscles and neurons and known to simultaneously bind both ER- and PM-localized ion channels. Since their discovery two decades ago, functional studies using junctophilin-deficient animals have provided a deep understanding of their roles in muscles and neurons, including excitation-contraction coupling, store-operated calcium entry (SOCE), and afterhyperpolarization (AHP). In this review, we highlight key findings from mouse, fly, and worm that support evolutionary conservation of junctophilins.
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Affiliation(s)
- Christopher A Piggott
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, San Diego, CA, United States
| | - Yishi Jin
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, San Diego, CA, United States
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