1
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Lahiri SK, Lu J, Aguilar-Sanchez Y, Li H, Moreira LM, Hulsurkar MM, Mendoza A, Turkieltaub Paredes MR, Navarro-Garcia JA, Munivez E, Horist B, Moore OM, Weninger G, Brandenburg S, Lenz C, Lehnart SE, Sayeed R, Krasopoulos G, Srivastava V, Zhang L, Karch JM, Reilly S, Wehrens XHT. Targeting calpain-2-mediated junctophilin-2 cleavage delays heart failure progression following myocardial infarction. J Mol Cell Cardiol 2024; 194:85-95. [PMID: 38960317 DOI: 10.1016/j.yjmcc.2024.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 06/18/2024] [Accepted: 06/29/2024] [Indexed: 07/05/2024]
Abstract
Coronary heart disease (CHD) is a prevalent cardiac disease that causes over 370,000 deaths annually in the USA. In CHD, occlusion of a coronary artery causes ischemia of the cardiac muscle, which results in myocardial infarction (MI). Junctophilin-2 (JPH2) is a membrane protein that ensures efficient calcium handling and proper excitation-contraction coupling. Studies have identified loss of JPH2 due to calpain-mediated proteolysis as a key pathogenic event in ischemia-induced heart failure (HF). Our findings show that calpain-2-mediated JPH2 cleavage yields increased levels of a C-terminal cleaved peptide (JPH2-CTP) in patients with ischemic cardiomyopathy and mice with experimental MI. We created a novel knock-in mouse model by removing residues 479-SPAGTPPQ-486 to prevent calpain-2-mediated cleavage at this site. Functional and molecular assessment of cardiac function post-MI in cleavage site deletion (CSD) mice showed preserved cardiac contractility and reduced dilation, reduced JPH2-CTP levels, attenuated adverse remodeling, improved T-tubular structure, and normalized SR Ca2+-handling. Adenovirus mediated calpain-2 knockdown in mice exhibited similar findings. Pulldown of CTP followed by proteomic analysis revealed valosin-containing protein (VCP) and BAG family molecular chaperone regulator 3 (BAG3) as novel binding partners of JPH2. Together, our findings suggest that blocking calpain-2-mediated JPH2 cleavage may be a promising new strategy for delaying the development of HF following MI.
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Affiliation(s)
- Satadru K Lahiri
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA
| | - Jiao Lu
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA; Development, Disease Models & Therapeutics Graduate Program, Baylor College of Medicine
| | - Yuriana Aguilar-Sanchez
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA
| | - Hui Li
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Lucia M Moreira
- Cardiovascular Medicine, Radcliffe Dept of Medicine, University of Oxford, UK
| | - Mohit M Hulsurkar
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA
| | - Arielys Mendoza
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA
| | - Mara R Turkieltaub Paredes
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA
| | - Jose Alberto Navarro-Garcia
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA
| | - Elda Munivez
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA
| | - Brooke Horist
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA
| | - Oliver M Moore
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA
| | - Gunnar Weninger
- Department of Physiology and Cellular Biophysics, Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Sören Brandenburg
- Department of Cardiology & Pneumology, Heart Research Center Göttingen; Cellular Biophysics and Translational Cardiology Section, University Medical Center Göttingen, Göttingen, Germany
| | - Christof Lenz
- Department of Clinical Chemistry, University Medical Center Göttingen, Germany; Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Stephan E Lehnart
- Department of Cardiology & Pneumology, Heart Research Center Göttingen; Cellular Biophysics and Translational Cardiology Section, University Medical Center Göttingen, Göttingen, Germany
| | - Rana Sayeed
- Cardiothoracic Unit, John Radcliffe Hospital, Oxford, UK
| | | | | | - Lilei Zhang
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Jason M Karch
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA
| | - Svetlana Reilly
- Cardiovascular Medicine, Radcliffe Dept of Medicine, University of Oxford, UK
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, USA; Department of Medicine/Cardiology, Baylor College of Medicine, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA; Center for Space Medicine, Baylor College of Medicine, Houston, TX, USA.
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2
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Agyapong ED, Pedriali G, Ramaccini D, Bouhamida E, Tremoli E, Giorgi C, Pinton P, Morciano G. Calcium signaling from sarcoplasmic reticulum and mitochondria contact sites in acute myocardial infarction. J Transl Med 2024; 22:552. [PMID: 38853272 PMCID: PMC11162575 DOI: 10.1186/s12967-024-05240-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 04/26/2024] [Indexed: 06/11/2024] Open
Abstract
Acute myocardial infarction (AMI) is a serious condition that occurs when part of the heart is subjected to ischemia episodes, following partial or complete occlusion of the epicardial coronary arteries. The resulting damage to heart muscle cells have a significant impact on patient's health and quality of life. About that, recent research focused on the role of the sarcoplasmic reticulum (SR) and mitochondria in the physiopathology of AMI. Moreover, SR and mitochondria get in touch each other through multiple membrane contact sites giving rise to the subcellular region called mitochondria-associated membranes (MAMs). MAMs are essential for, but not limited to, bioenergetics and cell fate. Disruption of the architecture of these regions occurs during AMI although it is still unclear the cause-consequence connection and a complete overview of the pathological changes; for sure this concurs to further damage to heart muscle. The calcium ion (Ca2+) plays a pivotal role in the pathophysiology of AMI and its dynamic signaling between the SR and mitochondria holds significant importance. In this review, we tried to summarize and update the knowledge about the roles of these organelles in AMI from a Ca2+ signaling point of view. Accordingly, we also reported some possible cardioprotective targets which are directly or indirectly related at limiting the dysfunctions caused by the deregulation of the Ca2+ signaling.
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Affiliation(s)
| | - Gaia Pedriali
- Maria Cecilia Hospital, GVM Care&Research, Cotignola, Italy
| | | | | | - Elena Tremoli
- Maria Cecilia Hospital, GVM Care&Research, Cotignola, Italy
| | - Carlotta Giorgi
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy.
- Maria Cecilia Hospital, GVM Care&Research, Cotignola, Italy.
| | - Giampaolo Morciano
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy.
- Maria Cecilia Hospital, GVM Care&Research, Cotignola, Italy.
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3
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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] [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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4
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Zhao R, Teng X, Yang Y. Calpain as a Therapeutic Target for Hypoxic-Ischemic Encephalopathy. Mol Neurobiol 2024; 61:533-540. [PMID: 37642934 DOI: 10.1007/s12035-023-03594-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 08/16/2023] [Indexed: 08/31/2023]
Abstract
Hypoxic-ischemic encephalopathy (HIE) is a complex pathophysiological process with multiple links and factors. It involves the interaction of inflammation, oxidative stress, and glucose metabolism, and results in acute and even long-term brain damage and impairment of brain function. Calpain is a family of Ca2+-dependent cysteine proteases that regulate cellular function. Calpain activation is involved in cerebral ischemic injury, and this involvement is achieved by the interaction among Ca2+, substrates, organelles, and multiple proteases in the neuronal necrosis and apoptosis pathways after cerebral ischemia. Many calpain inhibitors have been developed and tested in the biochemical and biomedical fields. This study reviewed the potential role of calpain in the treatment of HIE and related mechanism, providing new insights for future research on HIE.
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Affiliation(s)
- Ruiyang Zhao
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, 110004, Liaoning, China
| | - Xiufei Teng
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, 110004, Liaoning, China
| | - Yanchao Yang
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, 110004, Liaoning, China.
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5
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Hartley B, Bassiouni W, Schulz R, Julien O. The roles of intracellular proteolysis in cardiac ischemia-reperfusion injury. Basic Res Cardiol 2023; 118:38. [PMID: 37768438 DOI: 10.1007/s00395-023-01007-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/29/2023]
Abstract
Ischemic heart disease remains a leading cause of human mortality worldwide. One form of ischemic heart disease is ischemia-reperfusion injury caused by the reintroduction of blood supply to ischemic cardiac muscle. The short and long-term damage that occurs due to ischemia-reperfusion injury is partly due to the proteolysis of diverse protein substrates inside and outside of cardiomyocytes. Ischemia-reperfusion activates several diverse intracellular proteases, including, but not limited to, matrix metalloproteinases, calpains, cathepsins, and caspases. This review will focus on the biological roles, intracellular localization, proteolytic targets, and inhibitors of these proteases in cardiomyocytes following ischemia-reperfusion injury. Recognition of the intracellular function of each of these proteases includes defining their activation, proteolytic targets, and their inhibitors during myocardial ischemia-reperfusion injury. This review is a step toward a better understanding of protease activation and involvement in ischemic heart disease and developing new therapeutic strategies for its treatment.
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Affiliation(s)
- Bridgette Hartley
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | - Wesam Bassiouni
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Richard Schulz
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada.
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada.
- Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada.
| | - Olivier Julien
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.
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6
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Lee CS, Jung SY, Yee RSZ, Agha NH, Hong J, Chang T, Babcock LW, Fleischman JD, Clayton B, Hanna AD, Ward CS, Lanza D, Hurley AE, Zhang P, Wehrens XHT, Lagor WR, Rodney GG, Hamilton SL. Speg interactions that regulate the stability of excitation-contraction coupling protein complexes in triads and dyads. Commun Biol 2023; 6:942. [PMID: 37709832 PMCID: PMC10502019 DOI: 10.1038/s42003-023-05330-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 09/07/2023] [Indexed: 09/16/2023] Open
Abstract
Here we show that striated muscle preferentially expressed protein kinase α (Spegα) maintains cardiac function in hearts with Spegβ deficiency. Speg is required for stability of excitation-contraction coupling (ECC) complexes and interacts with esterase D (Esd), Cardiomyopathy-Associated Protein 5 (Cmya5), and Fibronectin Type III and SPRY Domain Containing 2 (Fsd2) in cardiac and skeletal muscle. Mice with a sequence encoding a V5/HA tag inserted into the first exon of the Speg gene (HA-Speg mice) display a >90% decrease in Spegβ but Spegα is expressed at ~50% of normal levels. Mice deficient in both Spegα and Speg β (Speg KO mice) develop a severe dilated cardiomyopathy and muscle weakness and atrophy, but HA-Speg mice display mild muscle weakness with no cardiac involvement. Spegα in HA-Speg mice suppresses Ca2+ leak, proteolytic cleavage of Jph2, and disruption of transverse tubules. Despite it's low levels, HA-Spegβ immunoprecipitation identified Esd, Cmya5 and Fsd2 as Spegβ binding partners that localize to triads and dyads to stabilize ECC complexes. This study suggests that Spegα and Spegβ display functional redundancy, identifies Esd, Cmya5 and Fsd2 as components of both cardiac dyads and skeletal muscle triads and lays the groundwork for the identification of new therapeutic targets for centronuclear myopathy.
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Affiliation(s)
- Chang Seok Lee
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Sung Yun Jung
- Department of Biochemistry, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Rachel Sue Zhen Yee
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Nadia H Agha
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Jin Hong
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Ting Chang
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Lyle W Babcock
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Jorie D Fleischman
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Benjamin Clayton
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Amy D Hanna
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Christopher S Ward
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Denise Lanza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Ayrea E Hurley
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Pumin Zhang
- The First Affiliated Hospital, Zhejiang University Medical School, Hangzhou, China
| | - Xander H T Wehrens
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - William R Lagor
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - George G Rodney
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Susan L Hamilton
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA.
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7
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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: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [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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8
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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] [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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9
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Yu L, Hall DD, Zhao W, Song LS. NMR resonance assignments of the DNA binding domain of mouse Junctophilin-2. BIOMOLECULAR NMR ASSIGNMENTS 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] [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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10
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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: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [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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11
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Chen Q, Thompson J, Hu Y, Lesnefsky EJ. The mitochondrial electron transport chain contributes to calpain 1 activation during ischemia-reperfusion. Biochem Biophys Res Commun 2022; 613:127-132. [PMID: 35550199 DOI: 10.1016/j.bbrc.2022.04.117] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 04/26/2022] [Indexed: 12/11/2022]
Abstract
Activation of calpain1 (CPN1) contributes to mitochondrial dysfunction during cardiac ischemia (ISC) - reperfusion (REP). Blockade of electron transport using amobarbital (AMO) protects mitochondria during ISC-REP, indicating that the electron transport chain (ETC) is a key source of mitochondrial injury. We asked if AMO treatment can decrease CPN1 activation as a potential mechanism of mitochondrial protection during ISC-REP. Buffer-perfused adult rat hearts underwent 25 min global ISC and 30 min REP. AMO (2.5 mM) or vehicle was administered for 1 min before ISC to block electron flow in the ETC. Hearts in the time control group were untreated and buffer perfused without ISC. Hearts were collected at the end of perfusion and used for mitochondrial isolation. ISC-REP increased both the cleavage of spectrin (indicating cytosolic CPN1 activation) in cytosol and the truncation of AIF (apoptosis inducing factor, indicating mitochondrial CPN1 activation) in subsarcolemmal mitochondria compared to time control. Thus, ISC-REP activated both cytosolic and mitochondrial CPN1. AMO treatment prevented the cleavage of spectrin and AIF during ISC-REP, suggesting that the transient blockade of electron transport during ISC decreases CPN1 activation. AMO treatment decreased the activation of PARP [poly(ADP-ribose) polymerase] downstream of AIF that triggers caspase-independent apoptosis. AMO treatment also decreased the release of cytochrome c from mitochondria during ISC-REP that prevented caspase 3 activation. These results support that the damaged ETC activates CPN1 in cytosol and mitochondria during ISC-REP, likely via calcium overload and oxidative stress. Thus, AMO treatment to mitigate mitochondrial-driven cardiac injury can decrease both caspase-dependent and caspase-independent programmed cell death during ISC-REP.
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Affiliation(s)
- Qun Chen
- Departments of Medicine (Division of Cardiology), Virginia Commonwealth University, Richmond, VA, 23298, USA.
| | - Jeremy Thompson
- Departments of Medicine (Division of Cardiology), Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Ying Hu
- Departments of Medicine (Division of Cardiology), Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Edward J Lesnefsky
- Departments of Medicine (Division of Cardiology), Virginia Commonwealth University, Richmond, VA, 23298, USA; Departments of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23298, USA; Departments of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, 23298, USA; Richmond Department of Veterans Affairs Medical Center, Richmond, VA, 23249, USA
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12
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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: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [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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13
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Aluja D, Delgado-Tomás S, Ruiz-Meana M, Barrabés JA, Inserte J. Calpains as Potential Therapeutic Targets for Myocardial Hypertrophy. Int J Mol Sci 2022; 23:ijms23084103. [PMID: 35456920 PMCID: PMC9032729 DOI: 10.3390/ijms23084103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 03/26/2022] [Accepted: 04/06/2022] [Indexed: 11/25/2022] Open
Abstract
Despite advances in its treatment, heart failure remains a major cause of morbidity and mortality, evidencing an urgent need for novel mechanism-based targets and strategies. Myocardial hypertrophy, caused by a wide variety of chronic stress stimuli, represents an independent risk factor for the development of heart failure, and its prevention constitutes a clinical objective. Recent studies performed in preclinical animal models support the contribution of the Ca2+-dependent cysteine proteases calpains in regulating the hypertrophic process and highlight the feasibility of their long-term inhibition as a pharmacological strategy. In this review, we discuss the existing evidence implicating calpains in the development of cardiac hypertrophy, as well as the latest advances in unraveling the underlying mechanisms. Finally, we provide an updated overview of calpain inhibitors that have been explored in preclinical models of cardiac hypertrophy and the progress made in developing new compounds that may serve for testing the efficacy of calpain inhibition in the treatment of pathological cardiac hypertrophy.
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Affiliation(s)
- David Aluja
- Cardiovascular Diseases Research Group, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Hospital Universitari, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (D.A.); (S.D.-T.); (M.R.-M.); (J.A.B.)
| | - Sara Delgado-Tomás
- Cardiovascular Diseases Research Group, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Hospital Universitari, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (D.A.); (S.D.-T.); (M.R.-M.); (J.A.B.)
| | - Marisol Ruiz-Meana
- Cardiovascular Diseases Research Group, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Hospital Universitari, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (D.A.); (S.D.-T.); (M.R.-M.); (J.A.B.)
- Centro de Investigación en Red de Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
| | - José A. Barrabés
- Cardiovascular Diseases Research Group, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Hospital Universitari, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (D.A.); (S.D.-T.); (M.R.-M.); (J.A.B.)
- Centro de Investigación en Red de Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
| | - Javier Inserte
- Cardiovascular Diseases Research Group, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Hospital Universitari, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (D.A.); (S.D.-T.); (M.R.-M.); (J.A.B.)
- Centro de Investigación en Red de Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
- Correspondence: ; Tel.: +34-934894038
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14
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Rossi D, Pierantozzi E, Amadsun DO, Buonocore S, Rubino EM, Sorrentino V. The Sarcoplasmic Reticulum of Skeletal Muscle Cells: A Labyrinth of Membrane Contact Sites. Biomolecules 2022; 12:488. [PMID: 35454077 PMCID: PMC9026860 DOI: 10.3390/biom12040488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/14/2022] [Accepted: 03/18/2022] [Indexed: 12/17/2022] Open
Abstract
The sarcoplasmic reticulum of skeletal muscle cells is a highly ordered structure consisting of an intricate network of tubules and cisternae specialized for regulating Ca2+ homeostasis in the context of muscle contraction. The sarcoplasmic reticulum contains several proteins, some of which support Ca2+ storage and release, while others regulate the formation and maintenance of this highly convoluted organelle and mediate the interaction with other components of the muscle fiber. In this review, some of the main issues concerning the biology of the sarcoplasmic reticulum will be described and discussed; particular attention will be addressed to the structure and function of the two domains of the sarcoplasmic reticulum supporting the excitation-contraction coupling and Ca2+-uptake mechanisms.
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Affiliation(s)
- Daniela Rossi
- Department of Molecular and Developmental Medicine, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy; (E.P.); (D.O.A.); (S.B.); (E.M.R.); (V.S.)
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15
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Chen Q, Thompson J, Hu Y, Lesnefsky EJ. Reversing mitochondrial defects in aged hearts: role of mitochondrial calpain activation. Am J Physiol Cell Physiol 2022; 322:C296-C310. [PMID: 35044856 PMCID: PMC8836732 DOI: 10.1152/ajpcell.00279.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 01/10/2022] [Accepted: 01/10/2022] [Indexed: 02/03/2023]
Abstract
Aging chronically increases endoplasmic reticulum (ER) stress that contributes to mitochondrial dysfunction. Activation of calpain 1 (CPN1) impairs mitochondrial function during acute ER stress. We proposed that aging-induced ER stress led to mitochondrial dysfunction by activating CPN1. We posit that attenuation of the ER stress or direct inhibition of CPN1 in aged hearts can decrease cardiac injury during ischemia-reperfusion by improving mitochondrial function. Male young (3 mo) and aged mice (24 mo) were used in the present study, and 4-phenylbutyrate (4-PBA) was used to decrease the ER stress in aged mice. Subsarcolemmal (SSM) and interfibrillar mitochondria (IFM) were isolated. Chronic 4-PBA treatment for 2 wk decreased CPN1 activation as shown by the decreased cleavage of spectrin in cytosol and apoptosis inducing factor (AIF) and the α1 subunit of pyruvate dehydrogenase (PDH) in mitochondria. Treatment improved oxidative phosphorylation in 24-mo-old SSM and IFM at baseline compared with vehicle. When 4-PBA-treated 24-mo-old hearts were subjected to ischemia-reperfusion, infarct size was decreased. These results support that attenuation of the ER stress decreased cardiac injury in aged hearts by improving mitochondrial function before ischemia. To challenge the role of CPN1 as an effector of the ER stress, aged mice were treated with MDL-28170 (MDL, an inhibitor of calpain 1). MDL treatment improved mitochondrial function in aged SSM and IFM. MDL-treated 24-mo-old hearts sustained less cardiac injury following ischemia-reperfusion. These results support that age-induced ER stress augments cardiac injury during ischemia-reperfusion by impairing mitochondrial function through activation of CPN1.
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Affiliation(s)
- Qun Chen
- Division of Cardiology, Department of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Jeremy Thompson
- Division of Cardiology, Department of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Ying Hu
- Division of Cardiology, Department of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Edward J Lesnefsky
- Division of Cardiology, Department of Medicine, Virginia Commonwealth University, Richmond, Virginia
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, Virginia
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia
- McGuire Department of Veterans Affairs Medical Center, Richmond, Virginia
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16
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Dixon RE. Nanoscale Organization, Regulation, and Dynamic Reorganization of Cardiac Calcium Channels. Front Physiol 2022; 12:810408. [PMID: 35069264 PMCID: PMC8769284 DOI: 10.3389/fphys.2021.810408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 11/30/2021] [Indexed: 12/19/2022] Open
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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17
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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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18
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Perni S. The Builders of the Junction: Roles of Junctophilin1 and Junctophilin2 in the Assembly of the Sarcoplasmic Reticulum–Plasma Membrane Junctions in Striated Muscle. Biomolecules 2022; 12:biom12010109. [PMID: 35053257 PMCID: PMC8774113 DOI: 10.3390/biom12010109] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 02/06/2023] Open
Abstract
Contraction of striated muscle is triggered by a massive release of calcium from the sarcoplasmic reticulum (SR) into the cytoplasm. This intracellular calcium release is initiated by membrane depolarization, which is sensed by voltage-gated calcium channels CaV1.1 (in skeletal muscle) and CaV1.2 (in cardiac muscle) in the plasma membrane (PM), which in turn activate the calcium-releasing channel ryanodine receptor (RyR) embedded in the SR membrane. This cross-communication between channels in the PM and in the SR happens at specialized regions, the SR-PM junctions, where these two compartments come in close proximity. Junctophilin1 and Junctophilin2 are responsible for the formation and stabilization of SR-PM junctions in striated muscle and actively participate in the recruitment of the two essential players in intracellular calcium release, CaV and RyR. This short review focuses on the roles of junctophilins1 and 2 in the formation and organization of SR-PM junctions in skeletal and cardiac muscle and on the functional consequences of the absence or malfunction of these proteins in striated muscle in light of recently published data and recent advancements in protein structure prediction.
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Affiliation(s)
- Stefano Perni
- Department of Physiology and Biophysics, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045, USA
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19
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Nakada T, Yamada M. [Regulation of localization and function of L-type calcium channels by junctophilins]. Nihon Yakurigaku Zasshi 2022; 157:4-8. [PMID: 34980811 DOI: 10.1254/fpj.21064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Striated muscle L-type calcium channels (LTCC) are localized specifically to the junctional membrane (JM) where the sarcolemma is closely apposed to the sarcoplasmic reticulum. Although this allocation of LTCC is critical for efficient excitation-contraction coupling in striated muscles, its underlying molecular mechanism has not been clarified. Junctophilins (JPs) stabilize the structure of JM by bridging the sarcolemmal and SR membranes. In addition, immunoprecipitation and pull-down assay revealed that the proximal C-terminus of CaV1.1 subunits directly binds to both JP1 and JP2, indicating that JPs might also directly recruit and hold LTCC in JM. Indeed, expression of a JP1 mutant lacking its C-terminus including the transmembrane domain in mouse skeletal muscles exerted a dominant-negative effect on endogenous JPs by impairing LTCC-RyR coupling at triads and reducing contractile force. To investigate a role of cardiac JP2 in a similar strategy, we injected adeno-associated virus vector expressing a C-terminus lacking JP2 mutant (JP2Δ427) driven by a cardiac troponin T promoter into C57BL/6 mice. Echocardiography recorded 4 weeks after the viral injection showed that the fractional shortening in JP2Δ427 group was significantly decreased compared to that of the control group. Calcium transient of isolated ventricular myocytes was significantly decreased by JP2Δ427 expression. Immunocytochemistry showed that JP2Δ427 recruited LTCC to the surface sarcolemma from T-tubules. Taken together, expression of C-terminus lacking JP mutants down-regulated contractile force by impairing ECC of skeletal and cardiac myocytes. Thus, the physical binding between LTCC and JP is essential for contraction of striated muscles.
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Affiliation(s)
- Tsutomu Nakada
- Department of Instrumental Analysis, Research Center for Advanced Science and Technology, Shinshu University.,Department of Molecular Pharmacology, Shinshu University School of Medicine
| | - Mitsuhiko Yamada
- Department of Molecular Pharmacology, Shinshu University School of Medicine
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The roles of cellular protease interactions in viral infections and programmed cell death: a lesson learned from the SARS-CoV-2 outbreak and COVID-19 pandemic. Pharmacol Rep 2022; 74:1149-1165. [PMID: 35997950 PMCID: PMC9395814 DOI: 10.1007/s43440-022-00394-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/03/2022] [Accepted: 07/18/2022] [Indexed: 12/13/2022]
Abstract
The unprecedented pandemic of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), which leads to COVID-19, is threatening global health. Over the last 2 years, we have witnessed rapid progress in research focusing on developing new antiviral vaccines and drugs, as well as in academic and clinical efforts to understand the biology and pathology of COVID-19. The roles of proteases among master regulators of SARS-CoV-2 invasion and replication and their pivotal roles in host defence against this pathogen, including programmed cell death, have not been well established. Our understanding of protease function in health and disease has increased considerably over the last two decades, with caspases, matrix metalloproteases, and transmembrane serine proteases representing the most prominent examples. Therefore, during the COVID-19 pandemic, these enzymes have been investigated as potential molecular targets for therapeutic interventions. Proteases that are responsible for SARS-CoV-2 cell entry and replication, such as TMPRSS2, ACE2 or cathepsins, are screened with inhibitor libraries to discover lead structures for further drug design that would prevent virus multiplication. On the other hand, proteases that orchestrate programmed cell death can also be harnessed to enhance the desired demise of infected cells through apoptosis or to attenuate highly inflammatory lytic cell death that leads to undesired cytokine storms, a major hallmark of severe COVID-19. Given the prominent role of proteases in SARS-CoV-2-induced cell death, we discuss the individual roles of these enzymes and their catalytic interactions in the pathology of COVID-19 in this article. We provide a rationale for targeting proteases participating in cell death as potential COVID-19 treatments and identify knowledge gaps that might be investigated to better understand the mechanism underlying SARS-CoV-2-induced cell death.
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21
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Quantitative Analysis of the Cardiac Phosphoproteome in Response to Acute β-Adrenergic Receptor Stimulation In Vivo. Int J Mol Sci 2021; 22:ijms222212584. [PMID: 34830474 PMCID: PMC8618155 DOI: 10.3390/ijms222212584] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/12/2021] [Accepted: 11/15/2021] [Indexed: 11/17/2022] Open
Abstract
β-adrenergic receptor (β-AR) stimulation represents a major mechanism of modulating cardiac output. In spite of its fundamental importance, its molecular basis on the level of cell signalling has not been characterised in detail yet. We employed mass spectrometry-based proteome and phosphoproteome analysis using SuperSILAC (spike-in stable isotope labelling by amino acids in cell culture) standardization to generate a comprehensive map of acute phosphoproteome changes in mice upon administration of isoprenaline (ISO), a synthetic β-AR agonist that targets both β1-AR and β2-AR subtypes. Our data describe 8597 quantitated phosphopeptides corresponding to 10,164 known and novel phospho-events from 2975 proteins. In total, 197 of these phospho-events showed significantly altered phosphorylation, indicating an intricate signalling network activated in response to β-AR stimulation. In addition, we unexpectedly detected significant cardiac expression and ISO-induced fragmentation of junctophilin-1, a junctophilin isoform hitherto only thought to be expressed in skeletal muscle. Data are available via ProteomeXchange with identifier PXD025569.
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22
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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] [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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23
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Calpain-2 specifically cleaves Junctophilin-2 at the same site as Calpain-1 but with less efficacy. Biochem J 2021; 478:3539-3553. [PMID: 34524407 PMCID: PMC8589432 DOI: 10.1042/bcj20210629] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [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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24
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Ling XX, Chen H, Fu BB, Ruan CS, Pana M, Zhou K, Fang ZR, Shao JT, Zhu FQ, Gao S. Xin-Ji-Er-Kang protects myocardial and renal injury in hypertensive heart failure in mice. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2021; 91:153675. [PMID: 34332285 DOI: 10.1016/j.phymed.2021.153675] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 05/27/2021] [Accepted: 07/14/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Xin-Ji-Er-Kang (XJEK) as a herbal formula of traditional Chinese medicine (TCM) has shown the protective effects on myocardial function as well as renal function in mouse models of myocardial infarction. HYPOTHESIS/PURPOSE We investigated the effects of XJEK on cardiovascular- and renal-function in a heart failure mouse model induced by high salt (HS) and the associated mechanisms. STUDY DESIGN For the purpose of assessing the effects of XJEK on a hypertensive heart failure model, mice were fed with 8% high salt diet. XJEK was administered by oral gavage for 8 weeks. Cardiovascular function parameters, renal function associated biomarkers and XJEK's impact on renin-angiotensin-aldosterone system (RAAS) activation were assessed. To determine the underlying mechanism, the calpain1/junctophilin-2 (JP2)/sarcoplasmic reticulum Ca2+ ATPase (SERCA2a) pathway was further studied in AC16 cells after angiotensin II-challenge or after calpastatin small interfering RNA (siRNA) transfection. RESULTS Mice on HS-diet exhibited hypertensive heart failure along with progressive kidney injury. Similar to fosinopril, XJEK ameliorated hypertension, cardiovascular-and renal- dysfunction in mice of HS-diet group. XJEK inhibited HS-induced activation of RAAS and reversed the abnormal expression pattern of calpain1and JP2 protein in heart tissues. XJEK significantly improved cell viability of angiotensin II-challenged AC16 cells. Moreover, XJEK's impact on calpain1/JP2 pathway was partly diminished in AC16 cells transfected with calpastatin siRNA. CONCLUSION XJEK was found to exert cardiovascular- and renal protection in HS-diet induced heart failure mouse model. XJEK inhibited HS-diet induced RAAS activation by inhibiting the activity and expression of calpain1 and protected the junctional membrane complex (JMC) in cardiomyocytes.
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Affiliation(s)
- Xin-Xin Ling
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China
| | - Hua Chen
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China
| | - Bei-Bei Fu
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China
| | - Cheng-Shao Ruan
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China
| | - Ming Pana
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China
| | - Kai Zhou
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China
| | - Zhi-Rui Fang
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China
| | - Jun-Tang Shao
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China.
| | - Feng-Qin Zhu
- Hefei Cancer Hospital, Chinese Academy of Science, Hefei 230032, China.
| | - Shan Gao
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China.
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25
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Setterberg IE, Le C, Frisk M, Li J, Louch WE. The Physiology and Pathophysiology of T-Tubules in the Heart. Front Physiol 2021; 12:718404. [PMID: 34566684 PMCID: PMC8458775 DOI: 10.3389/fphys.2021.718404] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/07/2021] [Indexed: 12/18/2022] Open
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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26
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Targeting JP2: A New Treatment for Pulmonary Hypertension. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:2003446. [PMID: 34394822 PMCID: PMC8363443 DOI: 10.1155/2021/2003446] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [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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27
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Piggott CA, Jin Y. Junctophilins: Key Membrane Tethers in Muscles and Neurons. Front Mol Neurosci 2021; 14:709390. [PMID: 34305529 PMCID: PMC8295595 DOI: 10.3389/fnmol.2021.709390] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 06/15/2021] [Indexed: 12/26/2022] Open
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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28
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Remodeling of t-system and proteins underlying excitation-contraction coupling in aging versus failing human heart. NPJ Aging Mech Dis 2021; 7:16. [PMID: 34050186 PMCID: PMC8163749 DOI: 10.1038/s41514-021-00066-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 04/26/2021] [Indexed: 11/14/2022] Open
Abstract
It is well established that the aging heart progressively remodels towards a senescent phenotype, but alterations of cellular microstructure and their differences to chronic heart failure (HF) associated remodeling remain ill-defined. Here, we show that the transverse tubular system (t-system) and proteins underlying excitation-contraction coupling in cardiomyocytes are characteristically remodeled with age. We shed light on mechanisms of this remodeling and identified similarities and differences to chronic HF. Using left ventricular myocardium from donors and HF patients with ages between 19 and 75 years, we established a library of 3D reconstructions of the t-system as well as ryanodine receptor (RyR) and junctophilin 2 (JPH2) clusters. Aging was characterized by t-system alterations and sarcolemmal dissociation of RyR clusters. This remodeling was less pronounced than in HF and accompanied by major alterations of JPH2 arrangement. Our study indicates that targeting sarcolemmal association of JPH2 might ameliorate age-associated deficiencies of heart function.
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29
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Preventing Myocardial Injury Following Non-Cardiac Surgery: A Potential Role for Preoperative Antioxidant Therapy with Ubiquinone. Antioxidants (Basel) 2021; 10:antiox10020276. [PMID: 33579045 PMCID: PMC7916807 DOI: 10.3390/antiox10020276] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/05/2021] [Accepted: 02/05/2021] [Indexed: 02/07/2023] Open
Abstract
Over 240 million non-cardiac operations occur each year and are associated with a 15-20% incidence of adverse perioperative cardiovascular events. Unfortunately, preoperative therapies that have been useful for chronic ischemic heart diseases, such as coronary artery revascularization, antiplatelet agents, and beta-blockers have failed to improve outcomes. In a pre-clinical swine model of ischemic heart disease, we showed that daily administration of ubiquinone (coenzyme Q10, CoQ10) enhances the antioxidant status of mitochondria within chronically ischemic heart tissue, potentially via a PGC1α-dependent mechanism. In a randomized controlled trial, among high-risk patients undergoing elective vascular surgery, we showed that NT Pro-BNP levels are an important means of risk-stratification during the perioperative period and can be lowered with administration of CoQ10 (400 mg/day) for 3 days prior to surgery. The review provides background information for the role of oxidant stress and inflammation during high-risk operations and the potential novel application of ubiquinone as a preoperative antioxidant therapy that might reduce perioperative adverse cardiovascular outcomes.
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30
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Wang S, Zhou Y, Luo Y, Kan R, Chen J, Xuan H, Wang C, Chen J, Xu T, Li D. SERCA2a ameliorates cardiomyocyte T-tubule remodeling via the calpain/JPH2 pathway to improve cardiac function in myocardial ischemia/reperfusion mice. Sci Rep 2021; 11:2037. [PMID: 33479390 PMCID: PMC7820433 DOI: 10.1038/s41598-021-81570-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 01/07/2021] [Indexed: 12/21/2022] Open
Abstract
Transverse-tubules (T-tubules) play pivotal roles in Ca2+-induced, Ca2+ release and excitation–contraction coupling in cardiomyocytes. The purpose of this study was to uncover mechanisms where sarco/endoplasmic reticulum Ca2+ ATPase (SERCA2a) improved cardiac function through T-tubule regulation during myocardial ischemia/reperfusion (I/R). SERCA2a protein expression, cytoplasmic [Ca2+]i, calpain activity, junctophilin-2 (JPH2) protein expression and intracellular localization, cardiomyocyte T-tubules, contractility and calcium transients in single cardiomyocytes and in vivo cardiac functions were all examined after SERCA2a knockout and overexpression, and Calpain inhibitor PD150606 (PD) pretreatment, following myocardial I/R. This comprehensive approach was adopted to clarify SERCA2a mechanisms in improving cardiac function in mice. Calpain was activated during myocardial I/R, and led to the proteolytic cleavage of JPH2. This altered the T-tubule network, the contraction function/calcium transients in cardiomyocytes and in vivo cardiac functions. During myocardial I/R, PD pretreatment upregulated JPH2 expression and restored it to its intracellular location, repaired the T-tubule network, and contraction function/calcium transients of cardiomyocytes and cardiac functions in vivo. SERCA2a suppressed calpain activity via [Ca2+]i, and ameliorated these key indices. Our results suggest that SERCA2a ameliorates cardiomyocyte T-tubule remodeling via the calpain/JPH2 pathway, thereby improving cardiac function in myocardial I/R mice.
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Affiliation(s)
- Shuai Wang
- Institute of Cardiovascular Disease Research, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, Jiangsu, People's Republic of China
| | - You Zhou
- Institute of Cardiovascular Disease Research, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, Jiangsu, People's Republic of China
| | - Yuanyuan Luo
- Department of Cardiology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou, 221006, Jiangsu, People's Republic of China
| | - Rongsheng Kan
- Institute of Cardiovascular Disease Research, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, Jiangsu, People's Republic of China
| | - Jingwen Chen
- Institute of Cardiovascular Disease Research, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, Jiangsu, People's Republic of China
| | - Haochen Xuan
- Department of Cardiology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou, 221006, Jiangsu, People's Republic of China
| | - Chaofan Wang
- Department of Cardiology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou, 221006, Jiangsu, People's Republic of China
| | - Junhong Chen
- Department of Cardiology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou, 221006, Jiangsu, People's Republic of China
| | - Tongda Xu
- Department of Cardiology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou, 221006, Jiangsu, People's Republic of China.
| | - Dongye Li
- Institute of Cardiovascular Disease Research, Xuzhou Medical University, 84 West Huaihai Road, Xuzhou, 221002, Jiangsu, People's Republic of China. .,Department of Cardiology, The Affiliated Hospital of Xuzhou Medical University, 99 West Huaihai Road, Xuzhou, 221006, Jiangsu, People's Republic of China.
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31
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Li S, Qian X, Gong J, Chen J, Tu W, Chen X, Chu M, Yang G, Li L, Jiang S. Exercise Training Reverses Lipotoxicity-induced Cardiomyopathy by Inhibiting HMGCS2. Med Sci Sports Exerc 2021; 53:47-57. [PMID: 32826638 DOI: 10.1249/mss.0000000000002453] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE This study aimed to determine the effect of exercise training on preventing lipotoxic cardiomyopathy and to investigate the role of the 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2) and miR-344g-5p in cardiomyocytes. METHODS Male C57BL/6 mice were fed a 60% high-fat diet (HFD) for 12 wk then began swimming exercise or remained sedentary for 8 wk. Thereafter, cardiac function was assessed by echocardiography, and heart tissue and plasma were collected for further measurements. The molecular mechanism of exercise was investigated after treating Hmgcs2 siRNA in palmitate-induced neonatal mouse cardiomyocytes. RESULTS HFD induced myocardial hypertrophy and fibrosis and reduced coronary reserve and cardiac function. HMGCS2 levels increased, but junctophilin-2 (JPH2) levels decreased in HFD mice hearts. Such effects were attenuated by swimming exercise. Mechanistically, Hmgcs2 silencing prevented apoptosis and caspase-3 cleavage and elevated the expression of JPH2 in palmitate-stimulated cardiomyocytes. In addition, exercise promoted miR-344g-5p expression in HFD hearts. The overexpression of miR-344g-5p by chemical mimic reduced HMGCS2, apoptosis, and caspase-3 cleavage and elevated JPH2 expression in palmitate-induced cardiomyocytes. CONCLUSION Our results suggest that exercise limits lipid metabolic disorder, cardiac hypertrophy, and fibrosis and aids in the prevention of lipotoxic cardiomyopathy. Exercise-mediated cardioprotection by upregulating miR-344g-5p, which targets Hmgcs2 mRNA, prohibits HMGCS2 upregulation and thus lipotoxicity.
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Affiliation(s)
| | | | | | | | | | | | - Maoping Chu
- Institute of Cardiovascular Development and Translational Medicine, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, CHINA
| | | | - Lei Li
- Institute of Cardiovascular Development and Translational Medicine, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, CHINA
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32
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Poulet C, Sanchez-Alonso J, Swiatlowska P, Mouy F, Lucarelli C, Alvarez-Laviada A, Gross P, Terracciano C, Houser S, Gorelik J. Junctophilin-2 tethers T-tubules and recruits functional L-type calcium channels to lipid rafts in adult cardiomyocytes. Cardiovasc Res 2021; 117:149-161. [PMID: 32053184 PMCID: PMC7797210 DOI: 10.1093/cvr/cvaa033] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 01/08/2020] [Accepted: 02/06/2020] [Indexed: 12/19/2022] Open
Abstract
AIM In cardiomyocytes, transverse tubules (T-tubules) associate with the sarcoplasmic reticulum (SR), forming junctional membrane complexes (JMCs) where L-type calcium channels (LTCCs) are juxtaposed to Ryanodine receptors (RyR). Junctophilin-2 (JPH2) supports the assembly of JMCs by tethering T-tubules to the SR membrane. T-tubule remodelling in cardiac diseases is associated with downregulation of JPH2 expression suggesting that JPH2 plays a crucial role in T-tubule stability. Furthermore, increasing evidence indicate that JPH2 might additionally act as a modulator of calcium signalling by directly regulating RyR and LTCCs. This study aimed at determining whether JPH2 overexpression restores normal T-tubule structure and LTCC function in cultured cardiomyocytes. METHODS AND RESULTS Rat ventricular myocytes kept in culture for 4 days showed extensive T-tubule remodelling with impaired JPH2 localization and relocation of the scaffolding protein Caveolin3 (Cav3) from the T-tubules to the outer membrane. Overexpression of JPH2 restored T-tubule structure and Cav3 relocation. Depletion of membrane cholesterol by chronic treatment with methyl-β-cyclodextrin (MβCD) countered the stabilizing effect of JPH2 overexpression on T-tubules and Cav3. Super-resolution scanning patch-clamp showed that JPH2 overexpression greatly increased the number of functional LTCCs at the plasma membrane. Treatment with MβCD reduced LTCC open probability and activity. Proximity ligation assays showed that MβCD did not affect JPH2 interaction with RyR and the pore-forming LTCC subunit Cav1.2, but strongly impaired JPH2 association with Cav3 and the accessory LTCC subunit Cavβ2. CONCLUSIONS JPH2 promotes T-tubule structural stability and recruits functional LTCCs to the membrane, most likely by directly binding to the channel. Cholesterol is involved in the binding of JPH2 to T-tubules as well as in the modulation of LTCC activity. We propose a model where cholesterol and Cav3 support the assembly of lipid rafts which provide an anchor for JPH2 to form JMCs and a platform for signalling complexes to regulate LTCC activity.
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Affiliation(s)
- Claire Poulet
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Jose Sanchez-Alonso
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Pamela Swiatlowska
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Florence Mouy
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Carla Lucarelli
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
- Department of Cardiac Surgery, School of Medicine, University of Verona, Piazzale L.A. Scuro 10, 37134 Verona, Italy
| | - Anita Alvarez-Laviada
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Polina Gross
- Cardiovascular Research Center, Lewis Katz School of Medicine, Temple University, 3500 N. Broad St., Philadelphia, PA 19140, USA
| | - Cesare Terracciano
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Steven Houser
- Cardiovascular Research Center, Lewis Katz School of Medicine, Temple University, 3500 N. Broad St., Philadelphia, PA 19140, USA
| | - Julia Gorelik
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
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T-tubule remodeling in human hypertrophic cardiomyopathy. J Muscle Res Cell Motil 2020; 42:305-322. [PMID: 33222034 PMCID: PMC8332592 DOI: 10.1007/s10974-020-09591-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 10/22/2020] [Indexed: 11/17/2022]
Abstract
The highly organized transverse T-tubule membrane system represents the ultrastructural substrate for excitation–contraction coupling in ventricular myocytes. While the architecture and function of T-tubules have been well described in animal models, there is limited morpho-functional data on T-tubules in human myocardium. Hypertrophic cardiomyopathy (HCM) is a primary disease of the heart muscle, characterized by different clinical presentations at the various stages of its progression. Most HCM patients, indeed, show a compensated hypertrophic disease (“non-failing hypertrophic phase”), with preserved left ventricular function, and only a small subset of individuals evolves into heart failure (“end stage HCM”). In terms of T-tubule remodeling, the “end-stage” disease does not differ from other forms of heart failure. In this review we aim to recapitulate the main structural features of T-tubules during the “non-failing hypertrophic stage” of human HCM by revisiting data obtained from human myectomy samples. Moreover, by comparing pathological changes observed in myectomy samples with those introduced by acute (experimentally induced) detubulation, we discuss the role of T-tubular disruption as a part of the complex excitation–contraction coupling remodeling process that occurs during disease progression. Lastly, we highlight how T-tubule morpho-functional changes may be related to patient genotype and we discuss the possibility of a primitive remodeling of the T-tubule system in rare HCM forms associated with genes coding for proteins implicated in T-tubule structural integrity, formation and maintenance.
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Lu F, Pu WT. The architecture and function of cardiac dyads. Biophys Rev 2020; 12:1007-1017. [PMID: 32661902 PMCID: PMC7429583 DOI: 10.1007/s12551-020-00729-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 07/03/2020] [Indexed: 12/28/2022] Open
Abstract
Cardiac excitation-contraction (EC) coupling, which links plasma membrane depolarization to activation of cardiomyocyte contraction, occurs at dyads, the nanoscopic microdomains formed by apposition of transverse (T)-tubules and junctional sarcoplasmic reticulum (jSR). In a dyadic junction, EC coupling occurs through Ca2+-induced Ca2+ release. Membrane depolarization opens voltage-gated L-type Ca2+ channels (LTCCs) in the T-tubule. The resulting influx of extracellular Ca2+ into the dyadic cleft opens Ca2+ release channels known as ryanodine receptors (RYRs) in the jSR, leading to the rapid increase in cytosolic Ca2+ that triggers sarcomere contraction. The efficacy of LTCC-RYR communication greatly affects a myriad of downstream intracellular signaling events, and it is controlled by many factors, including T-tubule and jSR structure, spatial distribution of ion channels, and regulatory proteins that closely regulate the activities of channels within dyads. Alterations in dyad architecture and/or channel activity are seen in many types of heart disease. This review will focus on the current knowledge regarding cardiac dyad structure and function, their alterations in heart failure, and new approaches to study the composition and function of dyads.
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Affiliation(s)
- Fujian Lu
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Ave, Boston, MA, 02115, USA
| | - William T Pu
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Ave, Boston, MA, 02115, USA.
- Harvard Stem Cell Institute, 7 Divinity Avenue, Cambridge, MA, 02138, USA.
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Nuclear localization of a novel calpain-2 mediated junctophilin-2 C-terminal cleavage peptide promotes cardiomyocyte remodeling. Basic Res Cardiol 2020; 115:49. [PMID: 32592107 PMCID: PMC10113426 DOI: 10.1007/s00395-020-0807-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 06/12/2020] [Indexed: 12/11/2022]
Abstract
Heart failure (HF) is a leading cause of morbidity and mortality worldwide. Patients with HF exhibit a loss of junctophilin-2 (JPH2), a structural protein critical in forming junctional membrane complexes in which excitation-contraction takes place. Several mechanisms have been proposed to mediate the loss of JPH2, one being cleavage by the calcium-dependent protease calpain. The downstream mechanisms underlying HF progression after JPH2 cleavage are presently poorly understood. In this study, we used Labcas to bioinformatically predict putative calpain cleavage sites on JPH2. We identified a cleavage site that produces a novel C-terminal JPH2 peptide (JPH2-CTP) using several domain-specific antibodies. Western blotting revealed elevated JPH2-CTP levels in hearts of patients and mice with HF, corresponding to increased levels of calpain-2. Moreover, immunocytochemistry demonstrated nuclear localization of JPH2-CTP within ventricular myocytes isolated from a murine model of pressure overload-induced HF as well as rat ventricular myocytes treated with isoproterenol. Nuclear localization of JPH2-CTP and cellular remodeling were abrogated by a genetic mutation of the nuclear localization sequence within JPH2-CTP. Taken together, our studies identified a novel C-terminal fragment of JPH2 (JPH2-CTP) generated by calpain-2 mediated cleavage which localizes within the cardiomyocyte nucleus during HF. Blocking nuclear localization of JPH2-CTP protects cardiomyocytes from isoproterenol-induced hypertrophy in vitro. Future in vivo studies of the nuclear role of JPH2-CTP may reveal a causal association with adverse remodeling during HF and establish CTP as a therapeutic target.
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Jin B, Ji F, Zuo A, Liu H, Qi L, He Y, Wang Q, Zhao P. Destructive Role of TMAO in T-Tubule and Excitation-Contraction Coupling in the Adult Cardiomyocytes. Int Heart J 2020; 61:355-363. [PMID: 32173700 DOI: 10.1536/ihj.19-372] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Heart failure (HF) is a disease with high morbidity and mortality. In patients with HF, decreased cardiac output and blood redistribution results in decreased intestinal perfusion and destruction of intestinal barrier. Microorganisms and endotoxins can migrate into the blood circulation, aggravating systemic inflammation and HF. Trimethylamine N-oxide (TMAO) is highly closed to the occurrence of HF. However, the exact mechanism between TMAO and HF remains unclear.To investigate the role of TMAO in transverse-tubule (T-tubule) in the cultured cardiomyocytes.T-tubule imaging and analysis detected T-tubule network in cardiomyocytes. Ca2+ handling dysfunction was identified by confocal Ca2+ imaging. Tubulin densification and polymerization were assessed by western blot and immunofluorescent staining of cardiomyocytes.TMAO induced T-tubule network damage in cardiomyocytes and Ca2+ handling dysfunction in cardiomyocytes under the TMAO stress via promoting tubulin densification and polymerization and therefore Junctophilin-2 (JPH2) redistribution. Mice treated with TMAO represented cardiac dysfunction and T-tubule network disorganization.TMAO impairs cardiac function via the promotion of tubulin polymerization, subsequent translocation of JPH2, and T-tubule remodeling, which provides a novel mechanism for the relationship between HF and elevated TMAO.
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Affiliation(s)
- Bu Jin
- Department of Pathology, the Affiliated Hospital of Qingdao University.,Department of Forensic Medicine, School of Basic Medicine, Qingdao University
| | - Fangfang Ji
- The Medical Examination Center of Shandong Province Sanatorium
| | - Anjun Zuo
- Department of General Surgery, the Affiliated Hospital of Qingdao University
| | - Huiting Liu
- Department of Pathology, the Affiliated Hospital of Qingdao University.,Department of Forensic Medicine, School of Basic Medicine, Qingdao University
| | - Lin Qi
- Department of Pathology, the Affiliated Hospital of Qingdao University.,Department of Forensic Medicine, School of Basic Medicine, Qingdao University
| | - Yun He
- Department of Pathology, the Affiliated Hospital of Qingdao University.,Department of Forensic Medicine, School of Basic Medicine, Qingdao University
| | - Qingyao Wang
- Department of Pathology, the Affiliated Hospital of Qingdao University.,Department of Forensic Medicine, School of Basic Medicine, Qingdao University
| | - Peng Zhao
- Department of Pathology, the Affiliated Hospital of Qingdao University.,Department of Forensic Medicine, School of Basic Medicine, Qingdao University
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Sun X, Sun Y, Jiang P, Qi G, Chen X. Crosstalk between endothelial cell-specific calpain inhibition and the endothelial-mesenchymal transition via the HSP90/Akt signaling pathway. Biomed Pharmacother 2020; 124:109822. [PMID: 31958767 DOI: 10.1016/j.biopha.2020.109822] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 12/28/2019] [Accepted: 12/29/2019] [Indexed: 12/15/2022] Open
Abstract
HYPOTHESIS The role of non-cardiomyocytes in cardiac remodeling and fibrosis has not been totally understood until now. This study investigated if endothelial cell (EC)-specific calpain participates in myocardial endothelial injury via the endothelial- mesenchymal transition (EndMT) and in cardiac fibroblasts during cell proliferation, thereby contributing to cardiac fibrosis eventually. METHODS in vitro cultured mouse cardiac ECs were induced with transforming growth factor (TGF)-β1 (10 ng/ml) and calpain inhibitor III (20 μM) or Akt inhibitor (LY294002, 20 μM). Isolated cardiac fibroblasts were induced by TGF-β1 and an HSP90 inhibitor (17AAG, 20 μM), and EndMT were analysed. Capn4-knockout (KO) specific to ECs of mice was generated. We induced the pathological process mimicking cardiac hypertrophy and fibrosis in both Capn4-KO mice and their wild-type littermates. The histological analysis was used to measure cardiomyocyte size and collagen contained in the heart. The immunofluorescence analysis was performed to demonstrate that the ECs went through the EndMT, transforming mesenchymal cells into fibroblasts and myofibroblasts. RESULTS Capn4 deletion specific to ECs abrogated activity of both calpain 1 and calpain 2 in ECs, lowered the volume of cardiac collagen and cardiomyocytes size, and ameliorated myocardial dysfunction in the isoproterenol-treated cardiac fibrosis model. An ex vivo analysis of cardiomyocytes by Evans Blue staining revealed that isoproterenol increased cell death compared with the control, and Capn4-KO alleviated this result. Inhibiting calpain in cultured cardiac microvascular endothelial cells (MCECs) reversed the EndMT process, which was induced by TGF-β1. Overexpression of calpastatin decreased the pathological EndMT process, showing that the cultured MCECs have more mesenchymal markers, such as α-smooth muscle actin (SMA), and fewer endothelial markers, such as VE-cadherin. Activating calpain elevated phosphorylated Akt in mice cultured ECs, and inhibiting calpain decreased phosphorylated Akt. Upregulation of phosphorylated Akt by calpain promoted the EndMT, whereas inhibiting calpain switched on the protective mechanism during the EndMT via the heat shock protein (HSP)90/Akt signaling way in cultured ECs. CONCLUSIONS This study demonstrated a vital role of calpain in ECs for inducing myocardiocyte hypertrophy, cell death and the EndMT via the HSP90/Akt signaling pathway, thereby promoting cardiac fibrosis. The results indicate that inhibiting ECs calpain is a novel therapeutic target to retard cardiac fibrosis and has positive effects on heart failure.
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Affiliation(s)
- Xiaodi Sun
- Department of Geriatric Cardiovascular Disease, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Yujiao Sun
- Department of Geriatric Cardiovascular Disease, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Pengcheng Jiang
- Department of Geriatric Cardiovascular Disease, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Guoxian Qi
- Department of Geriatric Cardiovascular Disease, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Xitao Chen
- Department of Thoracic Surgery, The First Affiliated Hospital of China Medical University, Shenyang, China.
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Adverse transverse-tubule remodeling in a rat model of heart failure is attenuated with low-dose triiodothyronine treatment. Mol Med 2019; 25:53. [PMID: 31810440 PMCID: PMC6898920 DOI: 10.1186/s10020-019-0120-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 11/18/2019] [Indexed: 12/24/2022] Open
Abstract
Abstract Pre-clinical animal studies have shown that triiodothyronine (T3) replacement therapy improves cardiac contractile function after myocardial infarction (MI). We hypothesized that T3 treatment could prevent adverse post-infarction cardiomyocyte remodeling by maintaining transverse-tubule (TT) structures, thus improving calcium dynamics and contractility. Methods Myocardial infarction (MI) or sham surgeries were performed on female Sprague-Dawley rats (aged 12 wks), followed by treatment with T3 (5μg/kg/d) or vehicle in drinking water for 16 wks (n = 10–11/group). After in vivo echocardiographic and hemodynamic analyses, left ventricular myocytes were isolated by collagenase digestion and simultaneous calcium and contractile transients in single cardiomyocytes were recorded using IonOptix imaging. Live cardiomyocytes were stained with AlexaFluor-488 conjugated wheat germ agglutinin (WGA-488) or di-8-ANEPPS, and multiple z-stack images per cell were captured by confocal microscopy for analysis of TT organization. RTqPCR and immunoblot approaches determined expression of TT proteins. Results Echocardiography and in vivo hemodynamic measurements showed significant improvements in systolic and diastolic function in T3- vs vehicle-treated MI rats. Isolated cardiomyocyte analysis showed significant dysfunction in measurements of myocyte relengthening in MI hearts, and improvements with T3 treatment: max relengthening velocity (Vmax, um/s), 2.984 ± 1.410 vs 1.593 ± 0.325, p < 0.05 and time to Vmax (sec), 0.233 ± 0.037 vs 0.314 ± 0.019, p < 0.001; MI + T3 vs MI + Veh, respectively. Time to peak contraction was shortened by T3 treatment (0.161 ± 0.021 vs 0.197 ± 0.011 s., p < 0.01; MI + T3 vs MI + Veh, respectively). Analysis of TT periodicity of WGA- or ANEPPS-stained cardiomyocytes indicated significant TT disorganization in MI myocytes and improvement with T3 treatment (transverse-oriented tubules (TE%): 9.07 ± 0.39 sham, 6.94 ± 0.67 MI + Veh and 8.99 ± 0.38 MI + T3; sham vs MI + Veh, p < 0.001; MI + Veh vs MI + T3, p < 0.01). Quantitative RT-PCR showed that reduced expression of BIN1 (Bridging integrator-1), Jph2 (junctophilin-2), RyR2 (ryanodine receptor) and Cav1.2 (L-type calcium channel) in the failing myocardium were increased by T3 and immunoblot analysis further supporting a potential T3 effect on the TT-associated proteins, BIN1 and Jph2. In conclusion, low dose T3 treatment initiated immediately after myocardial infarction attenuated adverse TT remodeling, improved calcium dynamics and contractility, thus supporting the potential therapeutic utility of T3 treatment in heart failure.
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Chan BYH, Roczkowsky A, Cho WJ, Poirier M, Lee TYT, Mahmud Z, Schulz R. Junctophilin-2 is a target of matrix metalloproteinase-2 in myocardial ischemia-reperfusion injury. Basic Res Cardiol 2019; 114:42. [PMID: 31506724 DOI: 10.1007/s00395-019-0749-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 09/02/2019] [Indexed: 11/30/2022]
Abstract
Junctophilin-2 is a structural membrane protein that tethers T-tubules to the sarcoplasmic reticulum to allow for coordinated calcium-induced calcium release in cardiomyocytes. Defective excitation-contraction coupling in myocardial ischemia-reperfusion (IR) injury is associated with junctophilin-2 proteolysis. However, it remains unclear whether preventing junctophilin-2 proteolysis improves the recovery of cardiac contractile dysfunction in IR injury. Matrix metalloproteinase-2 (MMP-2) is a zinc and calcium-dependent protease that is activated by oxidative stress in myocardial IR injury and cleaves both intracellular and extracellular substrates. To determine whether junctophilin-2 is targeted by MMP-2, isolated rat hearts were perfused in working mode aerobically or subjected to IR injury with the selective MMP inhibitor ARP-100. IR injury impaired the recovery of cardiac contractile function which was associated with increased degradation of junctophilin-2 and damaged cardiac dyads. In IR hearts, ARP-100 improved the recovery of cardiac contractile function, attenuated junctophilin-2 proteolysis, and prevented ultrastructural damage to the dyad. MMP-2 was co-localized with junctophilin-2 in aerobic and IR hearts by immunoprecipitation and immunohistochemistry. In situ zymography showed that MMP activity was localized to the Z-disc and sarcomere in aerobic hearts and accumulated at sites where the striated JPH-2 staining was disrupted in IR hearts. In vitro proteolysis assays determined that junctophilin-2 is susceptible to proteolysis by MMP-2 and in silico analysis predicted multiple MMP-2 cleavage sites between the membrane occupation and recognition nexus repeats and within the divergent region of junctophilin-2. Degradation of junctophilin-2 by MMP-2 is an early consequence of myocardial IR injury which may initiate a cascade of sequelae leading to impaired contractile function.
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Affiliation(s)
- Brandon Y H Chan
- Departments of Pediatrics and Pharmacology, Mazankowski Alberta Heart Institute, 462 Heritage Medical Research Centre, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Andrej Roczkowsky
- Departments of Pediatrics and Pharmacology, Mazankowski Alberta Heart Institute, 462 Heritage Medical Research Centre, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Woo Jung Cho
- Faculty of Medicine and Dentistry Cell Imaging Centre, University of Alberta, Edmonton, AB, Canada
| | - Mathieu Poirier
- Departments of Pediatrics and Pharmacology, Mazankowski Alberta Heart Institute, 462 Heritage Medical Research Centre, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Tim Y T Lee
- Departments of Pediatrics and Pharmacology, Mazankowski Alberta Heart Institute, 462 Heritage Medical Research Centre, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Zabed Mahmud
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | - Richard Schulz
- Departments of Pediatrics and Pharmacology, Mazankowski Alberta Heart Institute, 462 Heritage Medical Research Centre, University of Alberta, Edmonton, AB, T6G 2S2, Canada.
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Jiang M, Hu J, White FKH, Williamson J, Klymchenko AS, Murthy A, Workman SW, Tseng GN. S-Palmitoylation of junctophilin-2 is critical for its role in tethering the sarcoplasmic reticulum to the plasma membrane. J Biol Chem 2019; 294:13487-13501. [PMID: 31337710 DOI: 10.1074/jbc.ra118.006772] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 07/17/2019] [Indexed: 12/14/2022] Open
Abstract
Junctophilins (JPH1-JPH4) are expressed in excitable and nonexcitable cells, where they tether endoplasmic/sarcoplasmic reticulum (ER/SR) and plasma membranes (PM). These ER/SR-PM junctions bring Ca-release channels in the ER/SR and Ca as well as Ca-activated K channels in the PM to within 10-25 nm. Such proximity is critical for excitation-contraction coupling in muscles, Ca modulation of excitability in neurons, and Ca homeostasis in nonexcitable cells. JPHs are anchored in the ER/SR through the C-terminal transmembrane domain (TMD). Their N-terminal Membrane-Occupation-Recognition-Nexus (MORN) motifs can bind phospholipids. Whether MORN motifs alone are sufficient to stabilize JPH-PM binding is not clear. We investigate whether S-palmitoylation of cysteine (Cys), a critical mechanism controlling peripheral protein binding to PM, occurs in JPHs. We focus on JPH2 that has four Cys residues: three flanking the MORN motifs and one in the TMD. Using palmitate-alkyne labeling, Cu(I)-catalyzed alkyne-azide cycloaddition reaction with azide-conjugated biotin, immunoblotting, proximity-ligation-amplification, and various imaging techniques, we show that JPH2 is S-palmitoylatable, and palmitoylation is essential for its ER/SR-PM tether function. Palmitoylated JPH2 binds to lipid-raft domains in PM, whereas palmitoylation of TMD-located Cys stabilizes JPH2's anchor in the ER/SR membrane. Binding to lipid-raft domains protects JPH2 from depalmitoylation. Unpalmitoylated JPH2 is largely excluded from lipid rafts and loses the ability to form stable ER/SR-PM junctions. In adult ventricular myocytes, native JPH2 is S-palmitoylatable, and palmitoylated JPH2 forms distinct PM puncta. Sequence alignment reveals that the palmitoylatable Cys residues in JPH2 are conserved in other JPHs, suggesting that palmitoylation may also enhance ER/SR-PM tethering by these proteins.
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Affiliation(s)
- Min Jiang
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia 23298; Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Junping Hu
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Frances K H White
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Judy Williamson
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Andrey S Klymchenko
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 67401 Illkirch, France
| | - Akshay Murthy
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Samuel W Workman
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Gea-Ny Tseng
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia 23298.
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Brandenburg S, Pawlowitz J, Eikenbusch B, Peper J, Kohl T, Mitronova GY, Sossalla S, Hasenfuss G, Wehrens XH, Kohl P, Rog-Zielinska EA, Lehnart SE. Junctophilin-2 expression rescues atrial dysfunction through polyadic junctional membrane complex biogenesis. JCI Insight 2019; 4:127116. [PMID: 31217359 DOI: 10.1172/jci.insight.127116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 05/16/2019] [Indexed: 12/28/2022] Open
Abstract
Atrial dysfunction is highly prevalent and associated with increased severity of heart failure. While rapid excitation-contraction coupling depends on axial junctions in atrial myocytes, the molecular basis of atrial loss of function remains unclear. We identified approximately 5-fold lower junctophilin-2 levels in atrial compared with ventricular tissue in mouse and human hearts. In atrial myocytes, this resulted in subcellular expression of large junctophilin-2 clusters at axial junctions, together with highly phosphorylated ryanodine receptor (RyR2) channels. To investigate the contribution of junctophilin-2 to atrial pathology in adult hearts, we developed a cardiomyocyte-selective junctophilin-2-knockdown model with 0 mortality. Junctophilin-2 knockdown in mice disrupted atrial RyR2 clustering and contractility without hypertrophy or interstitial fibrosis. In contrast, aortic pressure overload resulted in left atrial hypertrophy with decreased junctophilin-2 and RyR2 expression, disrupted axial junctions, and atrial fibrosis. Whereas pressure overload accrued atrial dysfunction and heart failure with 40% mortality, additional junctophilin-2 knockdown greatly exacerbated atrial dysfunction with 100% mortality. Strikingly, transgenic junctophilin-2 overexpression restored atrial contractility and survival through de novo biogenesis of polyadic junctional membrane complexes maintained after pressure overload. Our data show a central role of junctophilin-2 cluster disruption in atrial hypertrophy and identify transgenic augmentation of junctophilin-2 as a disease-mitigating rationale to improve atrial dysfunction and prevent heart failure deterioration.
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Affiliation(s)
- Sören Brandenburg
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Jan Pawlowitz
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Benjamin Eikenbusch
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Jonas Peper
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Tobias Kohl
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Gyuzel Y Mitronova
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Samuel Sossalla
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Gerd Hasenfuss
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Xander Ht Wehrens
- Cardiovascular Research Institute - Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA
| | - Peter Kohl
- University Heart Center, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Eva A Rog-Zielinska
- University Heart Center, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Stephan E Lehnart
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany.,BioMET, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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42
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Jiang J, Tang M, Huang Z, Chen L. Junctophilins emerge as novel therapeutic targets. J Cell Physiol 2019; 234:16933-16943. [DOI: 10.1002/jcp.28405] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/25/2019] [Accepted: 01/30/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Jinyong Jiang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
| | - Mingzhu Tang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
| | - Zhen Huang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
| | - Linxi Chen
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
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43
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Padmanabhan A, Haldar SM. Unusual transcription factor protects against heart failure. Science 2018; 362:1359-1360. [DOI: 10.1126/science.aav8956] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Arun Padmanabhan
- Gladstone Institutes, San Francisco, CA, USA
- Division of Cardiology, Department of Medicine, University of California San Francisco School of Medicine, San Francisco, CA, USA
| | - Saptarsi M. Haldar
- Gladstone Institutes, San Francisco, CA, USA
- Division of Cardiology, Department of Medicine, University of California San Francisco School of Medicine, San Francisco, CA, USA
- Cardiometabolic Disorders, Amgen, South San Francisco, CA, USA
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44
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Jones PP, MacQuaide N, Louch WE. Dyadic Plasticity in Cardiomyocytes. Front Physiol 2018; 9:1773. [PMID: 30618792 PMCID: PMC6298195 DOI: 10.3389/fphys.2018.01773] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/23/2018] [Indexed: 11/13/2022] Open
Abstract
Contraction of cardiomyocytes is dependent on sub-cellular structures called dyads, where invaginations of the surface membrane (t-tubules) form functional junctions with the sarcoplasmic reticulum (SR). Within each dyad, Ca2+ entry through t-tubular L-type Ca2+ channels (LTCCs) elicits Ca2+ release from closely apposed Ryanodine Receptors (RyRs) in the SR membrane. The efficiency of this process is dependent on the density and macroscale arrangement of dyads, but also on the nanoscale organization of LTCCs and RyRs within them. We presently review accumulating data demonstrating the remarkable plasticity of these structures. Dyads are known to form gradually during development, with progressive assembly of both t-tubules and junctional SR terminals, and precise trafficking of LTCCs and RyRs. While dyads can exhibit compensatory remodeling when required, dyadic degradation is believed to promote impaired contractility and arrythmogenesis in cardiac disease. Recent data indicate that this plasticity of dyadic structure/function is dependent on the regulatory proteins junctophilin-2, amphiphysin-2 (BIN1), and caveolin-3, which critically arrange dyadic membranes while stabilizing the position and activity of LTCCs and RyRs. Indeed, emerging evidence indicates that clustering of both channels enables "coupled gating", implying that nanoscale localization and function are intimately linked, and may allow fine-tuning of LTCC-RyR crosstalk. We anticipate that improved understanding of dyadic plasticity will provide greater insight into the processes of cardiac compensation and decompensation, and new opportunities to target the basic mechanisms underlying heart disease.
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Affiliation(s)
- Peter P. Jones
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
- HeartOtago, University of Otago, Dunedin, New Zealand
| | - Niall MacQuaide
- Institute of Cardiovascular Sciences, University of Glasgow, Glasgow, United Kingdom
- Clyde Biosciences, Glasgow, United Kingdom
| | - William E. Louch
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway
- KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
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45
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Guo A, Wang Y, Chen B, Wang Y, Yuan J, Zhang L, Hall D, Wu J, Shi Y, Zhu Q, Chen C, Thiel WH, Zhan X, Weiss RM, Zhan F, Musselman CA, Pufall M, Zhu W, Au KF, Hong J, Anderson ME, Grueter CE, Song LS. E-C coupling structural protein junctophilin-2 encodes a stress-adaptive transcription regulator. Science 2018; 362:science.aan3303. [PMID: 30409805 DOI: 10.1126/science.aan3303] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 05/10/2018] [Accepted: 10/24/2018] [Indexed: 11/02/2022]
Abstract
Junctophilin-2 (JP2) is a structural protein required for normal excitation-contraction (E-C) coupling. After cardiac stress, JP2 is cleaved by the calcium ion-dependent protease calpain, which disrupts the E-C coupling ultrastructural machinery and drives heart failure progression. We found that stress-induced proteolysis of JP2 liberates an N-terminal fragment (JP2NT) that translocates to the nucleus, binds to genomic DNA, and controls expression of a spectrum of genes in cardiomyocytes. Transgenic overexpression of JP2NT in mice modifies the transcriptional profile, resulting in attenuated pathological remodeling in response to cardiac stress. Conversely, loss of nuclear JP2NT function accelerates stress-induced development of hypertrophy and heart failure in mutant mice. These data reveal a self-protective mechanism in failing cardiomyocytes that transduce mechanical information (E-C uncoupling) into salutary transcriptional reprogramming in the stressed heart.
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Affiliation(s)
- Ang Guo
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Yihui Wang
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.,Department of Emergency Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Biyi Chen
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Yunhao Wang
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Jinxiang Yuan
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Liyang Zhang
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Duane Hall
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Jennifer Wu
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Yun Shi
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Qi Zhu
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.,Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu 226001, China
| | - Cheng Chen
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.,Department of Emergency Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - William H Thiel
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Xin Zhan
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Robert M Weiss
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Fenghuang Zhan
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Catherine A Musselman
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Miles Pufall
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Weizhong Zhu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu 226001, China
| | - Kin Fai Au
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Jiang Hong
- Department of Emergency Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Mark E Anderson
- Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Chad E Grueter
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.,Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Long-Sheng Song
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, 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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46
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Ahmad S, Masjoan Juncos JX, Ahmad A, Zaky A, Wei CC, Bradley WE, Zafar I, Powell P, Mariappan N, Vetal N, Louch WE, Ford DA, Doran SF, Matalon S, Dell'Italia LJ. Bromine inhalation mimics ischemia-reperfusion cardiomyocyte injury and calpain activation in rats. Am J Physiol Heart Circ Physiol 2018; 316:H212-H223. [PMID: 30379573 DOI: 10.1152/ajpheart.00652.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Halogens are widely used, highly toxic chemicals that pose a potential threat to humans because of their abundance. Halogens such as bromine (Br2) cause severe pulmonary and systemic injuries; however, the mechanisms of their toxicity are largely unknown. Here, we demonstrated that Br2 and reactive brominated species produced in the lung and released in blood reach the heart and cause acute cardiac ultrastructural damage and dysfunction in rats. Br2-induced cardiac damage was demonstrated by acute (3-24 h) increases in circulating troponin I, heart-type fatty acid-binding protein, and NH2-terminal pro-brain natriuretic peptide. Transmission electron microscopy demonstrated acute (3-24 h) cardiac contraction band necrosis, disruption of z-disks, and mitochondrial swelling and disorganization. Echocardiography and hemodynamic analysis revealed left ventricular (LV) systolic and diastolic dysfunction at 7 days. Plasma and LV tissue had increased levels of brominated fatty acids. 2-Bromohexadecanal (Br-HDA) injected into the LV cavity of a normal rat caused acute LV enlargement with extensive disruption of the sarcomeric architecture and mitochondrial damage. There was extensive infiltration of neutrophils and increased myeloperoxidase levels in the hearts of Br2- or Br2 reactant-exposed rats. Increased bromination of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) and increased phosphalamban after Br2 inhalation decreased cardiac SERCA activity by 70%. SERCA inactivation was accompanied by increased Ca2+-sensitive LV calpain activity. The calpain-specific inhibitor MDL28170 administered within 1 h after exposure significantly decreased calpain activity and acute mortality. Bromine inhalation and formation of reactive brominated species caused acute cardiac injury and myocardial damage that can lead to heart failure. NEW & NOTEWORTHY The present study defines left ventricular systolic and diastolic dysfunction due to cardiac injury after bromine (Br2) inhalation. A calpain-dependent mechanism was identified as a potential mediator of cardiac ultrastructure damage. This study not only highlights the importance of monitoring acute cardiac symptoms in victims of Br2 exposure but also defines calpains as a potential target to treat Br2-induced toxicity.
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Affiliation(s)
- Shama Ahmad
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Juan Xavier Masjoan Juncos
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Aftab Ahmad
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Ahmed Zaky
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Chih-Chang Wei
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham , Birmingham, Alabama.,Department of Veterans Affairs Medical Center , Birmingham, Alabama
| | - Wayne E Bradley
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham , Birmingham, Alabama.,Department of Veterans Affairs Medical Center , Birmingham, Alabama
| | - Iram Zafar
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Pamela Powell
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham , Birmingham, Alabama.,Department of Veterans Affairs Medical Center , Birmingham, Alabama
| | - Nithya Mariappan
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Nilam Vetal
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo , Oslo , Norway.,KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - David A Ford
- Department of Biochemistry and Molecular Biology and Center for Cardiovascular Research, Saint Louis University , St. Louis, Missouri
| | - Stephen F Doran
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Sadis Matalon
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Louis J Dell'Italia
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham , Birmingham, Alabama.,Department of Veterans Affairs Medical Center , Birmingham, Alabama
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47
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Wang Y, Chen B, Huang CK, Guo A, Wu J, Zhang X, Chen R, Chen C, Kutschke W, Weiss RM, Boudreau RL, Margulies KB, Hong J, Song LS. Targeting Calpain for Heart Failure Therapy: Implications From Multiple Murine Models. JACC Basic Transl Sci 2018; 3:503-517. [PMID: 30175274 PMCID: PMC6115647 DOI: 10.1016/j.jacbts.2018.05.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 04/20/2018] [Accepted: 05/15/2018] [Indexed: 12/11/2022]
Abstract
Calpain is hyperactivated in human failing hearts and rodent heart failure models of different etiologies. Inhibition of calpain activity with MDL-28170 protects against cardiac dysfunction by preserving JP2 expression and T-tubule ultrastructural integrity in murine models of heart failure. Overexpression of JP2 delays the onset of early cardiac sudden death and heart failure, induced by calpain overactivation.
Heart failure remains a major cause of morbidity and mortality in developed countries. There is still a strong need to devise new mechanism-based treatments for heart failure. Numerous studies have suggested the importance of the Ca2+-dependent protease calpain in cardiac physiology and pathology. However, no drugs are currently under development or testing in human patients to target calpain for heart failure treatment. Herein the data demonstrate that inhibition of calpain activity protects against deleterious ultrastructural remodeling and cardiac dysfunction in multiple rodent models of heart failure, providing compelling evidence that calpain inhibition is a promising therapeutic strategy for heart failure treatment.
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Key Words
- CAPN1-OE, calpain-1 overexpressing
- E-C coupling, excitation-contraction coupling
- EF, ejection fraction
- IP, intraperitoneally
- ISO, isoproterenol
- JP2, junctophilin-2
- JP2-OE, junctophilin-2 overexpressing
- LV, left ventricle/ventricular
- MI, myocardial infarction
- RV, right ventricular
- SR, sarcoplasmic reticulum
- T-tubule, transverse tubule
- T-tubules
- TAB, transverse aortic banding
- TTpower, strength of regularity of the T-tubule system
- WT, wild-type
- calcium
- calpain
- excitation-contraction coupling
- heart failure
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Affiliation(s)
- Yihui Wang
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China.,Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Biyi Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa.,Department of Veterans Affairs Medical Center, Iowa City, Iowa
| | - Chun-Kai Huang
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China.,Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Ang Guo
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Jennifer Wu
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Xiaoming Zhang
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Rong Chen
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China.,Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Cheng Chen
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China.,Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - William Kutschke
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Robert M Weiss
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Ryan L Boudreau
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Kenneth B Margulies
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Jiang Hong
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Long-Sheng Song
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa.,Department of Veterans Affairs Medical Center, Iowa City, Iowa
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48
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Affiliation(s)
- Xander H.T. Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas
- Departments of Molecular Physiology & Biophysics, Department of Medicine (Cardiology), and Department of Pediatrics (Cardiology), Baylor College of Medicine, Houston, Texas
- Center for Space Medicine, Baylor College of Medicine, Houston, Texas
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49
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Guo A, Chen R, Wang Y, Huang CK, Chen B, Kutschke W, Hong J, Song LS. Transient activation of PKC results in long-lasting detrimental effects on systolic [Ca 2+] i in cardiomyocytes by altering actin cytoskeletal dynamics and T-tubule integrity. J Mol Cell Cardiol 2018; 115:104-114. [PMID: 29307535 DOI: 10.1016/j.yjmcc.2018.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/18/2017] [Accepted: 01/03/2018] [Indexed: 11/25/2022]
Abstract
AIMS Protein kinase C (PKC) isozymes contribute to the development of heart failure through dysregulation of Ca2+ handling properties and disruption of contractile function in cardiomyocytes. However, the mechanisms by which PKC activation leads to Ca2+ dysfunction are incompletely understood. METHODS AND RESULTS Shortly upon ventricular pressure overload in mice, we detected transient PKC activation that was associated with pulsed actin cytoskeletal rearrangement. In cultured cardiomyocytes, transient activation of PKC promoted long-term deleterious effects on the integrity of the transverse (T)- tubule system, resulting in a significant decrease in the amplitude and increase in the rising kinetics of Ca2+ transients. Treatment with a PKCα/β inhibitor restored the synchronization of Ca2+ transients and maintained T-tubule integrity in cultured cardiomyocytes. Supporting these data, PKCα/β inhibition protected against T-tubule remodeling and cardiac dysfunction in a mouse model of pressure overload-induced heart failure. Mechanistically, transient activation of PKC resulted in biphasic actin cytoskeletal rearrangement, consistent with in vivo observations in the pressure overloaded mouse model. Transient inhibition of actin polymerization or depolymerization resulted in severe T-tubule damage, recapitulating the T-tubule damage induced by PKC activation. Moreover, inhibition of stretch activated channels (SAC) protected against T-tubule remodeling and E-C coupling dysfunction induced by transient PKC activation and actin cytoskeletal rearrangement. CONCLUSIONS These data identify a key mechanistic link between transient PKC activation and long-term Ca2+ handling defects through PKC-induced actin cytoskeletal rearrangement and resultant T-tubule damage.
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Affiliation(s)
- Ang Guo
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Rong Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200080, China
| | - Yihui Wang
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200080, China
| | - Chun-Kai Huang
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200080, China
| | - Biyi Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - William Kutschke
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Jiang Hong
- Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200080, China
| | - Long-Sheng Song
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Department of Veterans Affairs Medical Center, Iowa City, IA 52242, USA.
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50
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Francois AA, Obasanjo-Blackshire K, Clark JE, Boguslavskyi A, Holt MR, Parker PJ, Marber MS, Heads RJ. Loss of Protein Kinase Novel 1 (PKN1) is associated with mild systolic and diastolic contractile dysfunction, increased phospholamban Thr17 phosphorylation, and exacerbated ischaemia-reperfusion injury. Cardiovasc Res 2018; 114:138-157. [PMID: 29045568 PMCID: PMC5815577 DOI: 10.1093/cvr/cvx206] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 03/17/2017] [Accepted: 10/13/2017] [Indexed: 01/20/2023] Open
Abstract
Aims PKN1 is a stress-responsive protein kinase acting downstream of small GTP-binding proteins of the Rho/Rac family. The aim was to determine its role in endogenous cardioprotection. Methods and results Hearts from PKN1 knockout (KO) or wild type (WT) littermate control mice were perfused in Langendorff mode and subjected to global ischaemia and reperfusion (I/R). Myocardial infarct size was doubled in PKN1 KO hearts compared to WT hearts. PKN1 was basally phosphorylated on the activation loop Thr778 PDK1 target site which was unchanged during I/R. However, phosphorylation of p42/p44-MAPK was decreased in KO hearts at baseline and during I/R. In cultured neonatal rat ventricular cardiomyocytes (NRVM) and NRVM transduced with kinase dead (KD) PKN1 K644R mutant subjected to simulated ischaemia/reperfusion (sI/R), PhosTag® gel analysis showed net dephosphorylation of PKN1 during sI and early R despite Thr778 phosphorylation. siRNA knockdown of PKN1 in NRVM significantly decreased cell survival and increased cell injury by sI/R which was reversed by WT- or KD-PKN1 expression. Confocal immunofluorescence analysis of PKN1 in NRVM showed increased localization to the sarcoplasmic reticulum (SR) during sI. GC-MS/MS and immunoblot analysis of PKN1 immunoprecipitates following sI/R confirmed interaction with CamKIIδ. Co-translocation of PKN1 and CamKIIδ to the SR/membrane fraction during sI correlated with phospholamban (PLB) Thr17 phosphorylation. siRNA knockdown of PKN1 in NRVM resulted in increased basal CamKIIδ activation and increased PLB Thr17 phosphorylation only during sI. In vivo PLB Thr17 phosphorylation, Sarco-Endoplasmic Reticulum Ca2+ ATPase (SERCA2) expression and Junctophilin-2 (Jph2) expression were also basally increased in PKN1 KO hearts. Furthermore, in vivo P-V loop analysis of the beat-to-beat relationship between rate of LV pressure development or relaxation and end diastolic P (EDP) showed mild but significant systolic and diastolic dysfunction with preserved ejection fraction in PKN1 KO hearts. Conclusion Loss of PKN1 in vivo significantly reduces endogenous cardioprotection and increases myocardial infarct size following I/R injury. Cardioprotection by PKN1 is associated with reduced CamKIIδ-dependent PLB Thr17 phosphorylation at the SR and therefore may stabilize the coupling of SR Ca2+ handling and contractile function, independent of its kinase activity.
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Affiliation(s)
- Asvi A Francois
- Department of Cardiology, School of Cardiovascular Medicine and Sciences, British Heart Foundation Centre for Research Excellence, Faculty of Life Sciences and Medicine, The Rayne Institute, King’s College London, St Thomas’s Hospital, Lambeth Palace Road, London, UK
| | - Kofo Obasanjo-Blackshire
- Department of Cardiology, School of Cardiovascular Medicine and Sciences, British Heart Foundation Centre for Research Excellence, Faculty of Life Sciences and Medicine, The Rayne Institute, King’s College London, St Thomas’s Hospital, Lambeth Palace Road, London, UK
| | - James E Clark
- Department of Cardiology, School of Cardiovascular Medicine and Sciences, British Heart Foundation Centre for Research Excellence, Faculty of Life Sciences and Medicine, The Rayne Institute, King’s College London, St Thomas’s Hospital, Lambeth Palace Road, London, UK
| | - Andrii Boguslavskyi
- Department of Cardiology, School of Cardiovascular Medicine and Sciences, British Heart Foundation Centre for Research Excellence, Faculty of Life Sciences and Medicine, The Rayne Institute, King’s College London, St Thomas’s Hospital, Lambeth Palace Road, London, UK
| | - Mark R Holt
- Department of Cardiology, School of Cardiovascular Medicine and Sciences, British Heart Foundation Centre for Research Excellence, Faculty of Life Sciences and Medicine, The Rayne Institute, King’s College London, St Thomas’s Hospital, Lambeth Palace Road, London, UK
- Randall Division of Cell and Molecular Biophysics, King’s College London, New Hunt’s House, Guy’s Hospital Campus, London, UK
| | - Peter J Parker
- Division of Cancer Studies, School of Cancer and Pharmaceutical Sciences, Faculty of Life Sciences and Medicine, King’s College London, New Hunt’s House, Guy’s Hospital Campus, London, UK
- Protein Phosphorylation Laboratory, Francis Crick Institute, Lincoln’s Inn Fields, London, UK
| | - Michael S Marber
- Department of Cardiology, School of Cardiovascular Medicine and Sciences, British Heart Foundation Centre for Research Excellence, Faculty of Life Sciences and Medicine, The Rayne Institute, King’s College London, St Thomas’s Hospital, Lambeth Palace Road, London, UK
| | - Richard J Heads
- Department of Cardiology, School of Cardiovascular Medicine and Sciences, British Heart Foundation Centre for Research Excellence, Faculty of Life Sciences and Medicine, The Rayne Institute, King’s College London, St Thomas’s Hospital, Lambeth Palace Road, London, UK
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