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Krishnan D, Pandey M, Nayak S, Ghosh SK. Novel Insights into the Wattle and Daub Model of Entamoeba Cyst Wall Formation and the Importance of Actin Cytoskeleton. Pathogens 2023; 13:20. [PMID: 38251328 PMCID: PMC10818507 DOI: 10.3390/pathogens13010020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/12/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024] Open
Abstract
The "Wattle and Daub" model of cyst wall formation in Entamoeba invadens has been used to explain encystment in Entamoeba histolytica, the causal agent of amoebiasis, and this process could be a potential target for new antiamoebic drugs. In this study, we studied the morphological stages of chitin wall formation in E. invadens in more detail using fluorescent chitin-binding dyes and the immunolocalization of cyst wall proteins. It was found that chitin deposition was mainly initiated on the cell surface at a specific point or at different points at the same time. The cystic wall grew outward and gradually covered the entire surface of the cyst over time, following the model of Wattle and Daub. The onset of chitin deposition was guided by the localization of chitin synthase 1 to the plasma membrane, occurring on the basis of the Jacob lectin in the cell membrane. During encystation, F-actin was reorganized into the cortical region within the early stages of encystation and remained intact until the completion of the chitin wall. The disruption of actin polymerization in the cortical region inhibited proper wall formation, producing wall-less cysts or cysts with defective chitin walls, indicating the importance of the cortical actin cytoskeleton for proper cyst wall formation.
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Affiliation(s)
| | | | | | - Sudip K. Ghosh
- Department of Bioscience and Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India; (D.K.); (M.P.); (S.N.)
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2
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Yang X, An N, Zhong C, Guan M, Jiang Y, Li X, Zhang H, Wang L, Ruan Y, Gao Y, Liu N, Shang H, Xing Y. Enhanced cardiomyocyte reactive oxygen species signaling promotes ibrutinib-induced atrial fibrillation. Redox Biol 2020; 30:101432. [PMID: 31986467 PMCID: PMC6994714 DOI: 10.1016/j.redox.2020.101432] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/27/2019] [Accepted: 01/12/2020] [Indexed: 12/12/2022] Open
Abstract
Atrial fibrillation (AF) occurs in up to 11% of cancer patients treated with ibrutinib. The pathophysiology of ibrutinib promoted AF is complicated, as there are multiple interactions involved; the detailed molecular mechanisms underlying this are still unclear. Here, we aimed to determine the electrophysiological and molecular mechanisms of burst-pacing-induced AF in ibrutinib-treated mice. The results indicated differentially expressed proteins in ibrutinib-treated mice, identified through proteomic analysis, were found to play a role in oxidative stress-related pathways. Finally, treatment with an inhibitor of NADPH oxidase (NOX) prevented and reversed AF development in ibrutinib-treated mice. It was showed that the related protein expression of reactive oxygen species (ROS) in the ibrutinib group was significantly increased, including NOX2, NOX4, p22-phox, XO and TGF-β protein expression. It was interesting that ibrutinib group also significantly increased the expression of ox-CaMKII, p-CaMKII (Thr-286) and p-RyR2 (Ser2814), causing enhanced abnormal sarcoplasmic reticulum (SR) Ca2+ release and mitochondrial structures, as well as atrial fibrosis and atrial hypertrophy in ibrutinib-treated mice, and apocynin reduced the expression of these proteins. Ibrutinib-treated mice were also more likely to develop AF, and AF occurred over longer periods. In conclusion, our study has established a pathophysiological role for ROS signaling in atrial cardiomyocytes, and it may be that ox-CaMKII and p-CaMKII (Thr-286) are activated by ROS to increase AF susceptibility following ibrutinib treatment. We have also identified the inhibition of NOX as a potential novel AF therapy approach.
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Affiliation(s)
- Xinyu Yang
- Key Laboratory of Chinese Internal Medicine of the Ministry of Education, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing, 100700, China; Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Na An
- Key Laboratory of Chinese Internal Medicine of the Ministry of Education, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing, 100700, China; Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Changming Zhong
- Key Laboratory of Chinese Internal Medicine of the Ministry of Education, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing, 100700, China
| | - Manke Guan
- Key Laboratory of Chinese Internal Medicine of the Ministry of Education, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing, 100700, China
| | - Yuchen Jiang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Xinye Li
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Hanlai Zhang
- Key Laboratory of Chinese Internal Medicine of the Ministry of Education, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing, 100700, China
| | - Liqin Wang
- Key Laboratory of Chinese Internal Medicine of the Ministry of Education, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing, 100700, China
| | - Yanfei Ruan
- Department of Cardiology, Beijing An Zhen Hospital of the Capital University of Medical Sciences, Beijing, 100853, PR China
| | - Yonghong Gao
- Key Laboratory of Chinese Internal Medicine of the Ministry of Education, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing, 100700, China
| | - Nian Liu
- Department of Cardiology, Beijing An Zhen Hospital of the Capital University of Medical Sciences, Beijing, 100853, PR China.
| | - Hongcai Shang
- Key Laboratory of Chinese Internal Medicine of the Ministry of Education, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing, 100700, China.
| | - Yanwei Xing
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
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3
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Yang H, Feng A, Lin S, Yu L, Lin X, Yan X, Lu X, Zhang C. Fibroblast growth factor-21 prevents diabetic cardiomyopathy via AMPK-mediated antioxidation and lipid-lowering effects in the heart. Cell Death Dis 2018; 9:227. [PMID: 29445083 PMCID: PMC5833682 DOI: 10.1038/s41419-018-0307-5] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 12/29/2017] [Accepted: 01/04/2018] [Indexed: 12/25/2022]
Abstract
Our previous studies showed that both exogenous and endogenous FGF21 inhibited cardiac apoptosis at the early stage of type 1 diabetes. Whether FGF21 induces preventive effect on type 2 diabetes-induced cardiomyopathy was investigated in the present study. High-fat-diet/streptozotocin-induced type 2 diabetes was established in both wild-type (WT) and FGF21-knockout (FGF21-KO) mice followed by treating with FGF21 for 4 months. Diabetic cardiomyopathy (DCM) was diagnosed by significant cardiac dysfunction, remodeling, and cardiac lipid accumulation associated with increased apoptosis, inflammation, and oxidative stress, which was aggravated in FGF21-KO mice. However, the cardiac damage above was prevented by administration of FGF21. Further studies demonstrated that the metabolic regulating effect of FGF21 is not enough, contributing to FGF21-induced significant cardiac protection under diabetic conditions. Therefore, other protective mechanisms must exist. The in vivo cardiac damage was mimicked in primary neonatal or adult mouse cardiomyocytes treated with HG/Pal, which was inhibited by FGF21 treatment. Knockdown of AMPKα1/2, AKT2, or NRF2 with their siRNAs revealed that FGF21 protected cardiomyocytes from HG/Pal partially via upregulating AMPK–AKT2–NRF2-mediated antioxidative pathway. Additionally, knockdown of AMPK suppressed fatty acid β-oxidation via inhibition of ACC–CPT-1 pathway. And, inhibition of fatty acid β-oxidation partially blocked FGF21-induced protection in cardiomyocytes. Further, in vitro and in vivo studies indicated that FGF21-induced cardiac protection against type 2 diabetes was mainly attributed to lipotoxicity rather than glucose toxicity. These results demonstrate that FGF21 functions physiologically and pharmacologically to prevent type 2 diabetic lipotoxicity-induced cardiomyopathy through activation of both AMPK–AKT2–NRF2-mediated antioxidative pathway and AMPK–ACC–CPT-1-mediated lipid-lowering effect in the heart.
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Affiliation(s)
- Hong Yang
- Ruian Center of Chinese-American Research Institute for Diabetic Complications, The Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Anyun Feng
- Ruian Center of Chinese-American Research Institute for Diabetic Complications, The Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Sundong Lin
- Chinese-American Research Institute for Diabetic Complications, Wenzhou Medical University, Wenzhou, China.,School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China
| | - Lechu Yu
- Ruian Center of Chinese-American Research Institute for Diabetic Complications, The Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xiufei Lin
- Ruian Center of Chinese-American Research Institute for Diabetic Complications, The Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.,Chinese-American Research Institute for Diabetic Complications, Wenzhou Medical University, Wenzhou, China.,School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China.,Wenzhou Biomedical Innovation Center, Wenzhou, China
| | - Xiaoqing Yan
- Ruian Center of Chinese-American Research Institute for Diabetic Complications, The Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.,Chinese-American Research Institute for Diabetic Complications, Wenzhou Medical University, Wenzhou, China.,School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China.,Wenzhou Biomedical Innovation Center, Wenzhou, China
| | - Xuemian Lu
- Ruian Center of Chinese-American Research Institute for Diabetic Complications, The Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
| | - Chi Zhang
- Ruian Center of Chinese-American Research Institute for Diabetic Complications, The Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China. .,Chinese-American Research Institute for Diabetic Complications, Wenzhou Medical University, Wenzhou, China. .,School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, China. .,Wenzhou Biomedical Innovation Center, Wenzhou, China.
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4
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Ackers-Johnson M, Li PY, Holmes AP, O'Brien SM, Pavlovic D, Foo RS. A Simplified, Langendorff-Free Method for Concomitant Isolation of Viable Cardiac Myocytes and Nonmyocytes From the Adult Mouse Heart. Circ Res 2016; 119:909-20. [PMID: 27502479 DOI: 10.1161/circresaha.116.309202] [Citation(s) in RCA: 315] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Accepted: 08/05/2016] [Indexed: 11/16/2022]
Abstract
RATIONALE Cardiovascular disease represents a global pandemic. The advent of and recent advances in mouse genomics, epigenomics, and transgenics offer ever-greater potential for powerful avenues of research. However, progress is often constrained by unique complexities associated with the isolation of viable myocytes from the adult mouse heart. Current protocols rely on retrograde aortic perfusion using specialized Langendorff apparatus, which poses considerable logistical and technical barriers to researchers and demands extensive training investment. OBJECTIVE To identify and optimize a convenient, alternative approach, allowing the robust isolation and culture of adult mouse cardiac myocytes using only common surgical and laboratory equipment. METHODS AND RESULTS Cardiac myocytes were isolated with yields comparable to those in published Langendorff-based methods, using direct needle perfusion of the LV ex vivo and without requirement for heparin injection. Isolated myocytes can be cultured antibiotic free, with retained organized contractile and mitochondrial morphology, transcriptional signatures, calcium handling, responses to hypoxia, neurohormonal stimulation, and electric pacing, and are amenable to patch clamp and adenoviral gene transfer techniques. Furthermore, the methodology permits concurrent isolation, separation, and coculture of myocyte and nonmyocyte cardiac populations. CONCLUSIONS We present a novel, simplified method, demonstrating concomitant isolation of viable cardiac myocytes and nonmyocytes from the same adult mouse heart. We anticipate that this new approach will expand and accelerate innovative research in the field of cardiac biology.
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Affiliation(s)
- Matthew Ackers-Johnson
- From the Cardiovascular Research Institute, Centre for Translational Medicine MD6, National University Health System, Singapore (M.A.-J., P.Y.L., R.S.F.); Genome Institute of Singapore (M.A.-J., R.S.F.); and Institute of Cardiovascular Sciences, University of Birmingham, UK (A.P.H., S.-M.O., D.P.)
| | - Peter Yiqing Li
- From the Cardiovascular Research Institute, Centre for Translational Medicine MD6, National University Health System, Singapore (M.A.-J., P.Y.L., R.S.F.); Genome Institute of Singapore (M.A.-J., R.S.F.); and Institute of Cardiovascular Sciences, University of Birmingham, UK (A.P.H., S.-M.O., D.P.)
| | - Andrew P Holmes
- From the Cardiovascular Research Institute, Centre for Translational Medicine MD6, National University Health System, Singapore (M.A.-J., P.Y.L., R.S.F.); Genome Institute of Singapore (M.A.-J., R.S.F.); and Institute of Cardiovascular Sciences, University of Birmingham, UK (A.P.H., S.-M.O., D.P.)
| | - Sian-Marie O'Brien
- From the Cardiovascular Research Institute, Centre for Translational Medicine MD6, National University Health System, Singapore (M.A.-J., P.Y.L., R.S.F.); Genome Institute of Singapore (M.A.-J., R.S.F.); and Institute of Cardiovascular Sciences, University of Birmingham, UK (A.P.H., S.-M.O., D.P.)
| | - Davor Pavlovic
- From the Cardiovascular Research Institute, Centre for Translational Medicine MD6, National University Health System, Singapore (M.A.-J., P.Y.L., R.S.F.); Genome Institute of Singapore (M.A.-J., R.S.F.); and Institute of Cardiovascular Sciences, University of Birmingham, UK (A.P.H., S.-M.O., D.P.)
| | - Roger S Foo
- From the Cardiovascular Research Institute, Centre for Translational Medicine MD6, National University Health System, Singapore (M.A.-J., P.Y.L., R.S.F.); Genome Institute of Singapore (M.A.-J., R.S.F.); and Institute of Cardiovascular Sciences, University of Birmingham, UK (A.P.H., S.-M.O., D.P.).
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5
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Cai WF, Liu GS, Lam CK, Florea S, Qian J, Zhao W, Pritchard T, Haghighi K, Lebeche D, Lu LJ, Deng J, Fan GC, Hajjar RJ, Kranias EG. Up-regulation of micro-RNA765 in human failing hearts is associated with post-transcriptional regulation of protein phosphatase inhibitor-1 and depressed contractility. Eur J Heart Fail 2015; 17:782-93. [PMID: 26177627 DOI: 10.1002/ejhf.323] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/18/2015] [Accepted: 04/17/2015] [Indexed: 11/09/2022] Open
Abstract
AIMS Impaired sarcoplasmic reticulum (SR) Ca(2+) cycling and depressed contractility, a hallmark of human and experimental heart failure, has been partially attributed to increased protein phosphatase 1 (PP-1) activity, associated with down-regulation of its endogenous inhibitor-1. The levels and activity of inhibitor-1 are reduced in failing hearts, contributing to dephosphorylation and inactivation of key calcium cycling proteins. Therefore, we investigated the mechanisms that mediate decreases in inhibitor-1 by post-transcriptional modification. METHODS AND RESULTS Bioinformatics revealed that 17 human microRNAs may serve as modulators of inhibitor-1. However, real-time PCR analysis identified only one of these microRNAs, miR-765, as being increased in human failing hearts concomitant with decreased inhibitor-1 levels. Expression of miR-765 in HEK293 cells or mouse ventricular myocytes confirmed suppression of inhibitor-1 levels through binding of this miR-765 to the 3'-untranslated region of inhibitor-1 mRNA. To determine the functional significance of miR-765 in Ca(2+) cycling, pri-miR-765 as well as a non-translated nucleotide sequence (miR-Ctrl) were expressed in adult mouse ventricular myocytes. The inhibitor-1 expression levels were decreased, accompanied by enhanced PP-1 activity in the miR-765 cardiomyocytes, and these reflected depressed contractile mechanics and Ca(2+) transients, compared with the miR-Ctrl group. The depressive effects were associated with decreases in the phosphorylation of phospholamban and SR Ca(2+) load. These miR-765 negative inotropic effects were abrogated in inhibitor-1-deficient cardiomyocytes, suggesting its apparent specificity for inhibitor-1. CONCLUSIONS miR-765 levels are increased in human failing hearts. Such increases may contribute to depressed cardiac function through reduced inhibitor-1 expression and enhanced PP-1 activity, associated with reduced SR Ca(2+) load.
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Affiliation(s)
- Wen-Feng Cai
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Guan-Sheng Liu
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Chi Keung Lam
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Stela Florea
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jiang Qian
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Wen Zhao
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Tracy Pritchard
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kobra Haghighi
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Djamel Lebeche
- Cardiovascular Research Center, Mount Sinai School of Medicine, New York, NY, USA
| | - Long Jason Lu
- Division of Biomedical Informatics, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH, USA
| | - Jingyuan Deng
- Division of Biomedical Informatics, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH, USA
| | - Guo-Chang Fan
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Roger J Hajjar
- Cardiovascular Research Center, Mount Sinai School of Medicine, New York, NY, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.,Molecular Biology Division, Center for Basic Research, Foundation for Biomedical Research of the Academy of Athens, Athens, Greece
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6
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Heiserman JP, Chen L, Kim BS, Kim SC, Tran AL, Siebenborn N, Knowlton AA. TLR4 mutation and HSP60-induced cell death in adult mouse cardiac myocytes. Cell Stress Chaperones 2015; 20:527-35. [PMID: 25716072 PMCID: PMC4406935 DOI: 10.1007/s12192-015-0577-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/06/2015] [Accepted: 02/11/2015] [Indexed: 01/04/2023] Open
Abstract
Extracellular (ex) HSP60 is increasingly recognized as an agent of cell injury. Previously, we reported that low endotoxin exHSP60 causes cardiac myocyte apoptosis. Our findings supported a role for Toll-like receptor (TLR) 4 in HSP60 mediated apoptosis. To further investigate the involvement of TLR4 in cardiac injury, we studied adult cardiac myocytes from C3H/HeJ (HeJ) mice, which have a mutant, nonfunctional TLR4, and compared the results with parallel studies using wild-type (WT) mice. Nuclear factor κB (NFκB) activation is an early step downstream of TLR4. NFκB was activated 1 h after treatment with HSP60 in WT, but not HeJ mouse myocytes. ExHSP60 caused apoptosis in cardiac myocytes from WT mice, but not in myocytes from the HeJ mutants. To further elucidate the importance of exHSP60 in cardiac myocyte injury, both WT and HeJ mutant isolated mouse adult cardiac myocytes were exposed to hypoxia/reoxygenation. Anti-HSP60 antibody treatment reduced apoptosis in the WT group, but had no effect on the HeJ mutant myocytes. Unexpectedly, necrosis was also decreased in the HeJ mutants. Necrosis after hypoxia/reoxygenation in WT cardiac myocytes was mediated in part by TLR2 and TLR4 through rapid activation of PKCα, followed by increased expression of Nox2, and this was ameliorated by blocking antibodies to TLR2/4. These studies provide further evidence that TLR4 mediates exHSP60-associated apoptosis and that exHSP60 has an important role in cardiac myocyte injury, both apoptotic and necrotic.
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Affiliation(s)
- J. P. Heiserman
- />Molecular and Cellular Cardiology, Department of Medicine, University of California, One Shields Avenue, Davis, CA 95616 USA
| | - L. Chen
- />Molecular and Cellular Cardiology, Department of Medicine, University of California, One Shields Avenue, Davis, CA 95616 USA
| | - B. S. Kim
- />Molecular and Cellular Cardiology, Department of Medicine, University of California, One Shields Avenue, Davis, CA 95616 USA
- />Division of Cardiology, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - S. C. Kim
- />Molecular and Cellular Cardiology, Department of Medicine, University of California, One Shields Avenue, Davis, CA 95616 USA
| | - A. L. Tran
- />Molecular and Cellular Cardiology, Department of Medicine, University of California, One Shields Avenue, Davis, CA 95616 USA
| | - N. Siebenborn
- />Molecular and Cellular Cardiology, Department of Medicine, University of California, One Shields Avenue, Davis, CA 95616 USA
| | - A. A. Knowlton
- />Molecular and Cellular Cardiology, Department of Medicine, University of California, One Shields Avenue, Davis, CA 95616 USA
- />VA Medical Center, Sacramento, CA USA
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7
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Figeac F, Lesault PF, Le Coz O, Damy T, Souktani R, Trébeau C, Schmitt A, Ribot J, Mounier R, Guguin A, Manier C, Surenaud M, Hittinger L, Dubois-Randé JL, Rodriguez AM. Nanotubular crosstalk with distressed cardiomyocytes stimulates the paracrine repair function of mesenchymal stem cells. Stem Cells 2014; 32:216-30. [PMID: 24115309 DOI: 10.1002/stem.1560] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 08/05/2013] [Indexed: 01/18/2023]
Abstract
Mesenchymal stem cells (MSC) are known to repair broken heart tissues primarily through a paracrine fashion while emerging evidence indicate that MSC can communicate with cardiomyocytes (CM) through tunneling nanotubes (TNT). Nevertheless, no link has been so far established between these two processes. Here, we addressed whether cell-to-cell communication processes between MSC and suffering cardiomyocytes and more particularly those involving TNT control the MSC paracrine regenerative function. In the attempt to mimic in vitro an injured heart microenvironment, we developed a species mismatch coculture system consisting of terminally differentiated CM from mouse in a distressed state and human multipotent adipose derived stem cells (hMADS). In this setting, we found that crosstalk between hMADS and CM through TNT altered the secretion by hMADS of cardioprotective soluble factors such as VEGF, HGF, SDF-1α, and MCP-3 and thereby maximized the capacity of stem cells to promote angiogenesis and chemotaxis of bone marrow multipotent cells. Additionally, engraftment experiments into mouse infarcted hearts revealed that in vitro preconditioning of hMADS with cardiomyocytes increased the cell therapy efficacy of naïve stem cells. In particular, in comparison with hearts treated with stem cells alone, those treated with cocultured ones exhibited greater cardiac function recovery associated with higher angiogenesis and homing of bone marrow progenitor cells at the infarction site. In conclusion, our findings established the first relationship between the paracrine regenerative action of MSC and the nanotubular crosstalk with CM and emphasize that ex vivo manipulation of these communication processes might be of interest for optimizing current cardiac cell therapies.
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Affiliation(s)
- Florence Figeac
- INSERM, U955, Créteil, France and Université Paris-Est, UMR_S955, UPEC, Créteil, France
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8
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Sowah D, Brown BF, Quon A, Alvarez BV, Casey JR. Resistance to cardiomyocyte hypertrophy in ae3-/- mice, deficient in the AE3 Cl-/HCO3- exchanger. BMC Cardiovasc Disord 2014; 14:89. [PMID: 25047106 PMCID: PMC4120010 DOI: 10.1186/1471-2261-14-89] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 07/16/2014] [Indexed: 12/21/2022] Open
Abstract
Background Cardiac hypertrophy is central to the etiology of heart failure. Understanding the molecular pathways promoting cardiac hypertrophy may identify new targets for therapeutic intervention. Sodium-proton exchanger (NHE1) activity and expression levels in the heart are elevated in many models of hypertrophy through protein kinase C (PKC)/MAPK/ERK/p90RSK pathway stimulation. Sustained NHE1 activity, however, requires an acid-loading pathway. Evidence suggests that the Cl−/HCO3− exchanger, AE3, provides this acid load. Here we explored the role of AE3 in the hypertrophic growth cascade of cardiomyocytes. Methods AE3-deficient (ae3−/−) mice were compared to wildtype (WT) littermates to examine the role of AE3 protein in the development of cardiomyocyte hypertrophy. Mouse hearts were assessed by echocardiography. As well, responses of cultured cardiomyocytes to hypertrophic stimuli were measured. pH regulation capacity of ae3−/− and WT cardiomyocytes was assessed in cultured cells loaded with the pH-sensitive dye, BCECF-AM. Results ae3−/− mice were indistinguishable from wild type (WT) mice in terms of cardiovascular performance. Stimulation of ae3−/− cardiomyocytes with hypertrophic agonists did not increase cardiac growth or reactivate the fetal gene program. ae3−/− mice are thus protected from pro-hypertrophic stimulation. Steady state intracellular pH (pHi) in ae3−/− cardiomyocytes was not significantly different from WT, but the rate of recovery of pHi from imposed alkalosis was significantly slower in ae3−/− cardiomyocytes. Conclusions These data reveal the importance of AE3-mediated Cl−/HCO3− exchange in cardiovascular pH regulation and the development of cardiomyocyte hypertrophy. Pharmacological antagonism of AE3 is an attractive approach in the treatment of cardiac hypertrophy.
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Affiliation(s)
| | | | | | | | - Joseph R Casey
- Department of Biochemistry and Membrane Protein Disease Research Group, University of Alberta, Edmonton T6G 2H7, Canada.
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9
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García-Prieto J, García-Ruiz JM, Sanz-Rosa D, Pun A, García-Alvarez A, Davidson SM, Fernández-Friera L, Nuno-Ayala M, Fernández-Jiménez R, Bernal JA, Izquierdo-Garcia JL, Jimenez-Borreguero J, Pizarro G, Ruiz-Cabello J, Macaya C, Fuster V, Yellon DM, Ibanez B. β3 adrenergic receptor selective stimulation during ischemia/reperfusion improves cardiac function in translational models through inhibition of mPTP opening in cardiomyocytes. Basic Res Cardiol 2014; 109:422. [PMID: 24951958 DOI: 10.1007/s00395-014-0422-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 06/10/2014] [Accepted: 06/11/2014] [Indexed: 01/19/2023]
Abstract
Selective stimulation of β3 adrenergic-receptor (β3AR) has been shown to reduce infarct size in a mouse model of myocardial ischemia/reperfusion. However, its functional long-term effect and the cardioprotective mechanisms at the level of cardiomyocytes have not been elucidated, and the impact of β3AR stimulation has not been evaluated in a more translational large animal model. This study aimed at evaluating pre-perfusion administration of BRL37344 both in small and large animal models of myocardial ischemia/reperfusion. Pre-reperfusion administration of the β3AR agonist BRL37344 (5 μg/kg) reduced infarct size at 2-and 24-h reperfusion in wild-type mice. Long-term (12-weeks) left ventricular (LV) function assessed by echocardiography and cardiac magnetic resonance (CMR) was significantly improved in β3AR agonist-treated mice. Incubation with β3AR agonist (BRL37344, 7 μmol/L) significantly reduced cell death in isolated adult mouse cardiomyocytes during hypoxia/reoxygenation and decreased susceptibility to deleterious opening of the mitochondrial permeability transition pore (mPTP), via a mechanism dependent on the Akt-NO signaling pathway. Pre-reperfusion BRL37344 administration had no effect on infarct size in cyclophilin-D KO mice, further implicating mPTP in the mechanism of protection. Large-white pigs underwent percutaneous coronary ischemia/reperfusion and 3-T CMR at 7 and 45 days post-infarction. Pre-perfusion administration of BRL37344 (5 μg/kg) decreased infarct size and improved long-term LV contractile function. A single-dose administration of β3AR agonist before reperfusion decreased infarct size and resulted in a consistent and long-term improvement in cardiac function, both in small and large animal models of myocardial ischemia/reperfusion. This protection appears to be executed through inhibition of mPTP opening in cardiomyocytes.
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MESH Headings
- Adrenergic beta-3 Receptor Agonists/pharmacology
- Animals
- Cardiotonic Agents/pharmacology
- Cell Death/drug effects
- Peptidyl-Prolyl Isomerase F
- Cyclophilins/deficiency
- Cyclophilins/genetics
- Disease Models, Animal
- Ethanolamines/pharmacology
- Magnetic Resonance Imaging
- Male
- Mice, Knockout
- Mitochondrial Membrane Transport Proteins/antagonists & inhibitors
- Mitochondrial Membrane Transport Proteins/metabolism
- Mitochondrial Permeability Transition Pore
- Myocardial Infarction/metabolism
- Myocardial Infarction/pathology
- Myocardial Infarction/physiopathology
- Myocardial Infarction/prevention & control
- Myocardial Reperfusion Injury/metabolism
- Myocardial Reperfusion Injury/pathology
- Myocardial Reperfusion Injury/physiopathology
- Myocardial Reperfusion Injury/prevention & control
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Nitric Oxide/metabolism
- Proto-Oncogene Proteins c-akt/metabolism
- Receptors, Adrenergic, beta-3/drug effects
- Receptors, Adrenergic, beta-3/metabolism
- Signal Transduction/drug effects
- Swine
- Time Factors
- Ventricular Function, Left/drug effects
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Affiliation(s)
- Jaime García-Prieto
- Imaging, Epidemiology and Atherothrombosis Department, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro 3, 28029, Madrid, Spain
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10
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Fine M, Lu FM, Lin MJ, Moe O, Wang HR, Hilgemann DW. Human-induced pluripotent stem cell-derived cardiomyocytes for studies of cardiac ion transporters. Am J Physiol Cell Physiol 2013; 305:C481-91. [PMID: 23804202 DOI: 10.1152/ajpcell.00143.2013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Human-induced pluripotent stem cells (hiPSCs) can differentiate into functional cardiomyocytes (iCell Cardiomyocytes) with ion channel activities that are remarkably similar to adult cardiomyocytes. Here, we extend this characterization to cardiac ion transporters. Additionally, we document facile molecular biological manipulation of iCell Cardiomyocytes to overexpress and knockdown transporters and regulatory proteins. Na/Ca exchange (NCX1) and Na/K pump currents were recorded via patch clamp, and Na/H and Cl/OH exchanges were recorded via oscillating proton-selective microelectrodes during patch clamp. Flux densities of all transport systems are similar to those of nonrodent adult cardiomyocytes. NCX1 protein and NCX1 currents decline after NCX1 small interfering (si)RNA transfection with similar time courses (τ ≈ 2 days), and an NCX1-Halo fusion protein is internalized after its extracellular labeling by AlexaFluor488 Ligand with a similar time course. Loss of the cardiac regulatory protein phospholemman (PLM) occurs over a longer time course (τ ≈ 60 h) after PLM small interfering RNA transfection. Similar to multiple previous reports for adult cardiomyocytes, Na/K pump currents in iCell Cardiomyocytes are not enhanced by activating cAMP production with either maximal or submaximal cytoplasmic Na and using either forskolin or isoproterenol to activate adenylate cyclases. Finally, we describe Ca influx-dependent changes of iCell Cardiomyocyte capacitance (Cm). Large increases of Cm occur during Ca influx via NCX1, thereby documenting large internal membrane reserves that can fuse to the sarcolemma, and subsequent declines of Cm document active endocytic processes. Together, these results document a great potential of iCell Cardiomyocytes for both short- and long-term studies of cardiac ion transporters and their regulation.
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Affiliation(s)
- Michael Fine
- Department of Physiology, University of Texas Southwestern Medical School, Dallas, Texas, USA
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11
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Kim M, Platt MJ, Shibasaki T, Quaggin SE, Backx PH, Seino S, Simpson JA, Drucker DJ. GLP-1 receptor activation and Epac2 link atrial natriuretic peptide secretion to control of blood pressure. Nat Med 2013; 19:567-75. [PMID: 23542788 DOI: 10.1038/nm.3128] [Citation(s) in RCA: 366] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 02/12/2013] [Indexed: 12/15/2022]
Abstract
Glucagon-like peptide-1 receptor (GLP-1R) agonists exert antihypertensive actions through incompletely understood mechanisms. Here we demonstrate that cardiac Glp1r expression is localized to cardiac atria and that GLP-1R activation promotes the secretion of atrial natriuretic peptide (ANP) and a reduction of blood pressure. Consistent with an indirect ANP-dependent mechanism for the antihypertensive effects of GLP-1R activation, the GLP-1R agonist liraglutide did not directly increase the amount of cyclic GMP (cGMP) or relax preconstricted aortic rings; however, conditioned medium from liraglutide-treated hearts relaxed aortic rings in an endothelium-independent, GLP-1R-dependent manner. Liraglutide did not induce ANP secretion, vasorelaxation or lower blood pressure in Glp1r(-/-) or Nppa(-/-) mice. Cardiomyocyte GLP-1R activation promoted the translocation of the Rap guanine nucleotide exchange factor Epac2 (also known as Rapgef4) to the membrane, whereas Epac2 deficiency eliminated GLP-1R-dependent stimulation of ANP secretion. Plasma ANP concentrations were increased after refeeding in wild-type but not Glp1r(-/-) mice, and liraglutide increased urine sodium excretion in wild-type but not Nppa(-/-) mice. These findings define a gut-heart GLP-1R-dependent and ANP-dependent axis that regulates blood pressure.
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Affiliation(s)
- Minsuk Kim
- Department of Medicine, Samuel Lunenfeld Research Institute, Mt. Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
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12
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Brown BF, Quon A, Dyck JRB, Casey JR. Carbonic anhydrase II promotes cardiomyocyte hypertrophy. Can J Physiol Pharmacol 2012; 90:1599-610. [PMID: 23210439 DOI: 10.1139/y2012-142] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Pathological cardiac hypertrophy, the maladaptive remodelling of the myocardium, often progresses to heart failure. The sodium-proton exchanger (NHE1) and chloride-bicarbonate exchanger (AE3) have been implicated as important in the hypertrophic cascade. Carbonic anhydrase II (CAII) provides substrates for these transporters (protons and bicarbonate, respectively). CAII physically interacts with NHE1 and AE3, enhancing their respective ion transport activities by increasing the concentration of substrate at their transport sites. Earlier studies found that a broad-spectrum carbonic anhydrase inhibitor prevented cardiomyocyte hypertrophy (CH), suggesting that carbonic anhydrase is important in the development of hypertrophy. Here we investigated whether cytosolic CAII was the CA isoform involved in hypertrophy. Neonatal rat ventricular myocytes (NRVMs) were transduced with recombinant adenoviral constructs to over-express wild-type or catalytically inactive CAII (CAII-V143Y). Over-expression of wild-type CAII in NRVMs did not affect CH development. In contrast, CAII-V143Y over-expression suppressed the response to hypertrophic stimuli, suggesting that CAII-V143Y behaves in a dominant negative fashion over endogenous CAII to suppress hypertrophy. We also examined CAII-deficient (Car2) mice, whose hearts exhibit physiological hypertrophy without any decrease in cardiac function. Moreover, cardiomyocytes from Car2 mice do not respond to prohypertrophic stimulation. Together, these findings support a role of CAII in promoting CH.
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Affiliation(s)
- Brittany F Brown
- Membrane Protein Disease Research Group, Department of Biochemistry, School of Translational Medicine, University of Alberta, Edmonton, AB, Canada
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13
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Ibarra C, Vicencio JM, Estrada M, Lin Y, Rocco P, Rebellato P, Munoz JP, Garcia-Prieto J, Quest AFG, Chiong M, Davidson SM, Bulatovic I, Grinnemo KH, Larsson O, Szabadkai G, Uhlén P, Jaimovich E, Lavandero S. Local control of nuclear calcium signaling in cardiac myocytes by perinuclear microdomains of sarcolemmal insulin-like growth factor 1 receptors. Circ Res 2012; 112:236-45. [PMID: 23118311 DOI: 10.1161/circresaha.112.273839] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
RATIONALE The ability of a cell to independently regulate nuclear and cytosolic Ca(2+) signaling is currently attributed to the differential distribution of inositol 1,4,5-trisphosphate receptor channel isoforms in the nucleoplasmic versus the endoplasmic reticulum. In cardiac myocytes, T-tubules confer the necessary compartmentation of Ca(2+) signals, which allows sarcomere contraction in response to plasma membrane depolarization, but whether there is a similar structure tunneling extracellular stimulation to control nuclear Ca(2+) signals locally has not been explored. OBJECTIVE To study the role of perinuclear sarcolemma in selective nuclear Ca(2+) signaling. METHODS AND RESULTS We report here that insulin-like growth factor 1 triggers a fast and independent nuclear Ca(2+) signal in neonatal rat cardiac myocytes, human embryonic cardiac myocytes, and adult rat cardiac myocytes. This fast and localized response is achieved by activation of insulin-like growth factor 1 receptor signaling complexes present in perinuclear invaginations of the plasma membrane. The perinuclear insulin-like growth factor 1 receptor pool connects extracellular stimulation to local activation of nuclear Ca(2+) signaling and transcriptional upregulation through the perinuclear hydrolysis of phosphatidylinositol 4,5-biphosphate inositol 1,4,5-trisphosphate production, nuclear Ca(2+) release, and activation of the transcription factor myocyte-enhancing factor 2C. Genetically engineered Ca(2+) buffers--parvalbumin--with cytosolic or nuclear localization demonstrated that the nuclear Ca(2+) handling system is physically and functionally segregated from the cytosolic Ca(2+) signaling machinery. CONCLUSIONS These data reveal the existence of an inositol 1,4,5-trisphosphate-dependent nuclear Ca(2+) toolkit located in direct apposition to the cell surface, which allows the local control of rapid and independent activation of nuclear Ca(2+) signaling in response to an extracellular ligand.
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Affiliation(s)
- Cristian Ibarra
- Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Quimicas y Farmaceuticas, Universidad de Chile, Santiago, Chile
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14
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Liu Y, Korte FS, Moussavi-Harami F, Yu M, Razumova M, Regnier M, Chin MT. Transcription factor CHF1/Hey2 regulates EC coupling and heart failure in mice through regulation of FKBP12.6. Am J Physiol Heart Circ Physiol 2012; 302:H1860-70. [PMID: 22408025 DOI: 10.1152/ajpheart.00702.2011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Heart failure is a leading cause of morbidity and mortality in Western society. The cardiovascular transcription factor CHF1/Hey2 has been linked to experimental heart failure in mice, but the mechanisms by which it regulates myocardial function remain incompletely understood. The objective of this study was to determine how CHF1/Hey2 affects development of heart failure through examination of contractility in a myocardial knockout mouse model. We generated myocardial-specific knockout mice. At baseline, cardiac function was normal, but, after aortic banding, the conditional knockout mice demonstrated a greater increase in ventricular weight-to-body weight ratio compared with control mice (5.526 vs. 4.664 mg/g) and a significantly decreased ejection fraction (47.8 vs. 72.0% control). Isolated cardiac myocytes from these mice showed decreased calcium transients and fractional shortening after electrical stimulation. To determine the molecular basis for these alterations in excitation-contraction coupling, we first measured total sarcoplasmic reticulum calcium stores and calcium-dependent force generation in isolated muscle fibers, which were normal, suggesting a defect in calcium cycling. Analysis of gene expression demonstrated normal expression of most genes known to be involved in myocardial calcium cycling, with the exception of the ryanodine receptor binding protein FKBP12.6, which was expressed at increased levels in the conditional knockout hearts. Treatment of the isolated knockout myocytes with FK506, which inhibits the association of FKBP12.6 with the ryanodine receptor, restored contractile function. These findings demonstrate that conditional deletion of CHF1/Hey2 in the myocardium leads to abnormalities in calcium handling mediated by FKBP12.6 that predispose to pressure overload-induced heart failure.
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Affiliation(s)
- Yonggang Liu
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington 98109, USA
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15
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Yang X, Chen G, Papp R, Defranco DB, Zeng F, Salama G. Oestrogen upregulates L-type Ca²⁺ channels via oestrogen-receptor- by a regional genomic mechanism in female rabbit hearts. J Physiol 2011; 590:493-508. [PMID: 22124151 DOI: 10.1113/jphysiol.2011.219501] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In type-2 long QT (LQT2), adult women and adolescent boys have a higher risk of lethal arrhythmias, called Torsades de pointes (TdP), compared to the opposite sex. In rabbit hearts, similar sex- and age-dependent TdP risks were attributed to higher expression levels of L-type Ca(2+) channels and Na(+)-Ca(2+) exchanger, at the base of the female epicardium. Here, the effects of oestrogen and progesterone are investigated to elucidate the mechanisms whereby I(Ca,L) density is upregulated in adult female rabbit hearts. I(Ca,L) density was measured by the whole-cell patch-clamp technique on days 0-3 in cardiomyocytes isolated from the base and apex of adult female epicardium. Peak I(Ca,L) was 28% higher at the base than apex (P < 0.01) and decreased gradually (days 0-3), becoming similar to apex myocytes, which had stable currents for 3 days. Incubation with oestrogen (E2, 0.1-1.0 nm) increased I(Ca,L) (∼2-fold) in female base but not endo-, apex or male myocytes. Progesterone (0.1-10 μm) had no effect at base myocytes. An agonist of the α- (PPT, 5 nm) but not the β- (DPN, 5 nm) subtype oestrogen receptor (ERα/ERβ) upregulated I(Ca,L) like E2. Western blots detected similar levels of ERα and ERβ in male and female hearts at the base and apex. E2 increased Cav1.2α (immunocytochemistry) and mRNA (RT-PCR) levels but did not change I(Ca,L) kinetics. I(Ca,L) upregulation by E2 was suppressed by the ER antagonist ICI 182,780 (10 μm) or by inhibition of transcription (actinomycin D, 4 μm) or protein biosynthesis (cycloheximide, 70 μm). Therefore, E2 upregulates I(Ca,L) by a regional genomic mechanism involving ERα which is a known determinant of sex differences in TdP risk in LQT2.
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Affiliation(s)
- Xiaoyan Yang
- University of Pittsburgh, Department of Medicine, Cardiovascular Institute, 3550 Terrace Street, Suite S 628 Scaife Hall, Pittsburgh, PA 15261, USA
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16
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Andersson DC, Fauconnier J, Park CB, Zhang SJ, Thireau J, Ivarsson N, Larsson NG, Westerblad H. Enhanced cardiomyocyte Ca(2+) cycling precedes terminal AV-block in mitochondrial cardiomyopathy Mterf3 KO mice. Antioxid Redox Signal 2011; 15:2455-64. [PMID: 21381862 DOI: 10.1089/ars.2011.3915] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
AIMS Heart disease is commonly associated with altered mitochondrial function and signs of oxidative stress. This study elucidates whether primary cardiac mitochondrial dysfunction causes changes in cardiomyocyte handling of reactive oxygen species (ROS) and Ca(2+). We used a mouse model with a tissue-specific ablation of the recently discovered mtDNA transcription regulator Mterf3 (Mterf3 KO). These mice display a cardiomyopathy with severe respiratory chain dysfunction, cardiac hypertrophy, and shortened lifespan. ROS and Ca(2+) handling were measured using fluorescent indicators and confocal microscopy. RESULTS Mterf3 KO hearts displayed no signs of increased ROS production or oxidative stress. Surprisingly, Mterf3 KO cardiomyocytes showed enlarged Ca(2+) transient amplitudes, faster sarcoplasmic reticulum (SR) Ca(2+) reuptake, and increased SR Ca(2+) load, resembling increased adrenergic stimulation. Furthermore, spontaneous releases of Ca(2+) were frequent in Mterf3 KO cardiomyocytes. Electrocardiography (measured with telemetry in freely moving mice) showed a terminal state in Mterf3 KO mice with gradually developing bradycardia and atrioventricular block. CONCLUSION In conclusion, mitochondrial dysfunction induced by Mterf3 KO leads to a cardiomyopathy without signs of oxidative stress but with increased cardiomyocyte Ca(2+) cycling and an arrhythmogenic phenotype. These findings highlight the complex interaction between mitochondrial function, cardiomyocyte contractility, and compensatory mechanisms, such as activation of adrenergic signaling.
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Affiliation(s)
- Daniel C Andersson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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17
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Li C, Li J, Cai X, Sun H, Jiao J, Bai T, Zhou XW, Chen X, Gill DL, Tang XD. Protein kinase D3 is a pivotal activator of pathological cardiac hypertrophy by selectively increasing the expression of hypertrophic transcription factors. J Biol Chem 2011; 286:40782-91. [PMID: 21971046 DOI: 10.1074/jbc.m111.263046] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Fetal cardiac gene reactivation is a hallmark of pathological cardiac hypertrophy (PCH) driven by cardiac transcription factors (TFs) such as nuclear factor of activated T-cells (NFATs). Nuclear import of dephosphorylated NFATs catalyzed by calcineurin (CaN) is a well-established hypertrophic mechanism. Here we report that NFATc4 expression is also up-regulated by newly expressed protein kinase D3 (PKD3) to induce PCH. In both in vitro and in vivo cardiac hypertrophic models, the normally undetectable PKD3 was profoundly up-regulated by isoproterenol followed by overt expression of cardiac TFs including NFATc4, NK family of transcription factor 2.5 (Nkx2.5), GATA4 and myocyte enhancer factor 2 (MEF2). Using gene silencing approaches, we demonstrate PKD3 is required for increasing the expression of NFATc4, Nkx2.5, and GATA4 while PKD1 is required for the increase in MEF2D expression. Upstream induction of PKD3 is driven by nuclear entry of CaN-activated NFATc1 and c3 but not c4. Therefore, PKD3 is a pivotal mediator of the CaN-NFATc1/c3-PKD3-NFATc4 hypertrophic signaling cascade and a potential new drug target for the PCH.
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Affiliation(s)
- Changlin Li
- Department of Pharmacology, Nankai University School of Medicine, Nankai, Tianjin 300071, China
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18
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Hedhli N, Huang Q, Kalinowski A, Palmeri M, Hu X, Russell RR, Russell KS. Endothelium-derived neuregulin protects the heart against ischemic injury. Circulation 2011; 123:2254-62. [PMID: 21555713 DOI: 10.1161/circulationaha.110.991125] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Removal of cardiac endothelial cells (EC) has been shown to produce significant detrimental effects on the function of adjacent cardiac myocytes, suggesting that EC play a critical role in autocrine/paracrine regulation of the heart. Despite this important observation, the mediators of the protective function of EC remain obscure. Neuregulin (NRG, a member of the epidermal growth factor family) is produced by EC and cardiac myocytes contain receptors (erbB) for this ligand. We hypothesized that NRG is an essential factor produced by EC, which promotes cardioprotection against ischemic injury. METHODS AND RESULTS We demonstrate that human cardiac EC express and release NRG in response to hypoxia-reoxygenation. Under conditions where hypoxia--reoxygenation causes significant cardiac myocyte cell death, NRG can significantly decrease apoptosis of isolated adult ventricular myocytes. Coculturing adult murine myocytes with human umbilical vein, murine lung microvascular, or human coronary artery EC can also protect myocytes against hypoxia--reoxygenation--induced apoptosis. These protective effects are abolished by NRG gene deletion or silencing of NRG expression in EC. Finally, endothelium-selective deletion of NRG in vivo leads to significantly decreased tolerance to ischemic insult, as demonstrated by impaired postischemic contractile recovery in a perfused whole-organ preparation and larger infarct sizes after coronary artery ligation. CONCLUSION Together, these data demonstrate that EC-derived NRG plays an important role in cardiac myocyte protection against ischemic injury in the heart and supports the idea that manipulation of this signaling pathway may be an important clinical target in this setting.
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Affiliation(s)
- Nadia Hedhli
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
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19
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The δA isoform of calmodulin kinase II mediates pathological cardiac hypertrophy by interfering with the HDAC4-MEF2 signaling pathway. Biochem Biophys Res Commun 2011; 409:125-30. [PMID: 21554860 DOI: 10.1016/j.bbrc.2011.04.128] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Accepted: 04/27/2011] [Indexed: 11/20/2022]
Abstract
Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is a new promising target for prevention and treatment of cardiac hypertrophy and heart failure. There are three δ isoforms of CaMKII in the heart and previous studies focused primarily on δB and δC types. Here we report the δA isoform of CaMKII is also critically involved in cardiac hypertrophy. We found that δA was significantly upregulated in pathological cardiac hypertrophy in both neonatal and adult models. Upregulation of δA was accompanied by cell enlargement, sarcomere reorganization and reactivation of various hypertrophic cardiac genes including atrial natriuretic factor (ANF) and β-myocin heavy chain (β-MHC). Studies further indicated the pathological changes were largely blunted by silencing the δA gene and an underlying mechanism indicated selective interference with the HDAC4-MEF2 signaling pathway. These results provide new evidence for selective interfering cardiac hypertrophy and heart failure when CaMKII is considered as a therapeutic target.
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20
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Acquistapace A, Bru T, Lesault PF, Figeac F, Coudert AE, Le Coz O, Christov C, Baudin X, Auber F, Yiou R, Dubois-Randé JL, Rodriguez AM. Human mesenchymal stem cells reprogram adult cardiomyocytes toward a progenitor-like state through partial cell fusion and mitochondria transfer. Stem Cells 2011; 29:812-24. [PMID: 21433223 PMCID: PMC3346716 DOI: 10.1002/stem.632] [Citation(s) in RCA: 192] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Because stem cells are often found to improve repair tissue including heart without evidence of engraftment or differentiation, mechanisms underlying wound healing are still elusive. Several studies have reported that stem cells can fuse with cardiomyocytes either by permanent or partial cell fusion processes. However, the respective physiological impact of these two processes remains unknown in part because of the lack of knowledge of the resulting hybrid cells. To further characterize cell fusion, we cocultured mouse fully differentiated cardiomyocytes with human multipotent adipose-derived stem (hMADS) cells as a model of adult stem cells. We found that heterologous cell fusion promoted cardiomyocyte reprogramming back to a progenitor-like state. The resulting hybrid cells expressed early cardiac commitment and proliferation markers such as GATA-4, myocyte enhancer factor 2C, Nkx2.5, and Ki67 and exhibited a mouse genotype. Interestingly, human bone marrow-derived stem cells shared similar reprogramming properties than hMADS cells but not human fibroblasts, which suggests that these features might be common to multipotent cells. Furthermore, cardiac hybrid cells were preferentially generated by partial rather than permanent cell fusion and that intercellular structures composed of f-actin and microtubule filaments were involved in the process. Finally, we showed that stem cell mitochondria were transferred into cardiomyocytes, persisted in hybrids and were required for somatic cell reprogramming. In conclusion, by providing new insights into previously reported cell fusion processes, our data might contribute to a better understanding of stem cell-mediated regenerative mechanisms and thus, the development of more efficient stem cell-based heart therapies.
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Affiliation(s)
- Adrien Acquistapace
- Institut Mondor de Recherche Biomédicale
INSERM : U955Université Paris XII Val de MarneIFR1094010 Créteil, FR
| | - Thierry Bru
- Institut Mondor de Recherche Biomédicale
INSERM : U955Université Paris XII Val de MarneIFR1094010 Créteil, FR
| | - Pierre-François Lesault
- Institut Mondor de Recherche Biomédicale
INSERM : U955Université Paris XII Val de MarneIFR1094010 Créteil, FR
| | - Florence Figeac
- Institut Mondor de Recherche Biomédicale
INSERM : U955Université Paris XII Val de MarneIFR1094010 Créteil, FR
| | - Amélie E. Coudert
- Institut Mondor de Recherche Biomédicale
INSERM : U955Université Paris XII Val de MarneIFR1094010 Créteil, FR
| | - Olivier Le Coz
- Institut Mondor de Recherche Biomédicale
INSERM : U955Université Paris XII Val de MarneIFR1094010 Créteil, FR
| | - Christo Christov
- Institut Mondor de Recherche Biomédicale
INSERM : U955Université Paris XII Val de MarneIFR1094010 Créteil, FR
| | - Xavier Baudin
- IJM, Institut Jacques Monod
CNRS : UMR7592Université Paris Diderot - Paris 7Batiment Buffon 15 rue Hélène Brion 75205 Paris cédex 13,FR
| | - Fréderic Auber
- Service de chirurgie pédiatrique viscérale et néonatale
Assistance publique - Hôpitaux de Paris (AP-HP)Hôpital Armand Trousseau75012 Paris,FR
| | - René Yiou
- Institut Mondor de Recherche Biomédicale
INSERM : U955Université Paris XII Val de MarneIFR1094010 Créteil, FR
| | - Jean-Luc Dubois-Randé
- Institut Mondor de Recherche Biomédicale
INSERM : U955Université Paris XII Val de MarneIFR1094010 Créteil, FR
| | - Anne-Marie Rodriguez
- Institut Mondor de Recherche Biomédicale
INSERM : U955Université Paris XII Val de MarneIFR1094010 Créteil, FR
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21
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Andersson DC, Fauconnier J, Yamada T, Lacampagne A, Zhang SJ, Katz A, Westerblad H. Mitochondrial production of reactive oxygen species contributes to the β-adrenergic stimulation of mouse cardiomycytes. J Physiol 2011; 589:1791-801. [PMID: 21486840 DOI: 10.1113/jphysiol.2010.202838] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The sympathetic adrenergic system plays a central role in stress signalling and stress is often associated with increased production of reactive oxygen species (ROS). Furthermore, the sympathetic adrenergic system is intimately involved in the regulation of cardiomyocyte Ca2+ handling and contractility. In this study we hypothesize that endogenously produced ROS contribute to the inotropic mechanism of β-adrenergic stimulation in mouse cardiomyocytes. Cytoplasmic Ca2+ transients, cell shortening and ROS production were measured in freshly isolated cardiomyocytes using confocal microscopy and fluorescent indicators. As a marker of oxidative stress, malondialdehyde (MDA) modification of proteins was detected with Western blotting. Isoproterenol (ISO), a β-adrenergic agonist, increased mitochondrial ROS production in cardiomyocytes in a concentration- and cAMP–protein kinase A-dependent but Ca2+-independent manner. Hearts perfused with ISO showed a twofold increase in MDA protein adducts relative to control. ISO increased Ca2+ transient amplitude, contraction and L-type Ca2+ current densities (measured with whole-cell patch-clamp) in cardiomyocytes and these increases were diminished by application of the general antioxidant N-acetylcysteine (NAC) or the mitochondria-targeted antioxidant SS31. In conclusion, increased mitochondrial ROS production plays an integral role in the acute inotropic response of cardiomyocytes to β-adrenergic stimulation. On the other hand, chronically sustained adrenergic stress is associated with the development of heart failure and cardiac arrhythmias and prolonged increases in ROS may contribute to these defects.
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Affiliation(s)
- Daniel C Andersson
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden
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22
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Chen G, Yang X, Alber S, Shusterman V, Salama G. Regional genomic regulation of cardiac sodium-calcium exchanger by oestrogen. J Physiol 2011; 589:1061-80. [PMID: 21224239 DOI: 10.1113/jphysiol.2010.203398] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Female rabbit hearts are more susceptible to torsade de pointes (TdP) in acquired long QT type 2 than males, in-part due to higher L-type Ca2+ current (ICa,L) at the base of the heart. In principle, higher Ca2+ influx via ICa,L should be balanced by higher efflux, perhaps mediated by parallel sex differences of sodium-calcium exchange (NCX) current (INCX). We now show that NCX1, like Cav1.2α, is greater at the base of female than male left ventricular epicardium and greater at the base than at the apex in both sexes. In voltage-clamp studies, inward (0, +20 mV, P < 0.04) and outward (-80, -60, -40, -20 mV, P < 0.01) INCX densities were significantly higher (1.5-2 fold) in female base compared to apex and male (base and apex) myocytes. Myocytes were incubated ±17β-oestradiol (E2 = 1 nm) and INCX was measured on days 0, 1, 2 and 3. Inward and outward INCX decreased over 2 days in female base myocytes becoming similar to INCX at the apex. E2 incubation (24 h) increased NCX1 (50%) and INCX (∼3-fold at 60 mV) in female base but not endocardium, apex or in male base myocytes. INCX upregulation by E2 was blunted by an oestrogen receptor (ER) antagonist (fulvestrant, 1 μm), and inhibition of transcription (actinomycin D, 5 μg ml-1) or translation (cycloheximide, 20 μg ml-1). Dofetilide (an IKr blocker) induced early afterdepolarizations (EADs) in female base myocytes cultured for 1 day if incubated with E2, but not without E2 or with E2+KB-R4973 (an INCX inhibitor), E2+fulvestrant or E2 with apex myocytes. Thus, E2 upregulates NCX1 by a genomic mechanism mediated by ERs, and de novo mRNA and protein biosynthesis, in a sex- and region-dependent manner which contributes to the enhanced propensity to EADs and TdP in female hearts.
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Affiliation(s)
- Guojun Chen
- University of Pittsburgh, School of Medicine, Cardiovascular Institute, 3550 Terrace Street, Suite S 628 Scaife Hall, Pittsburgh, PA 15261, USA
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Mansén A, Tiselius C, Sand P, Fauconnier J, Westerblad H, Rydqvist B, Vennström B. Thyroid hormone receptor alpha can control action potential duration in mouse ventricular myocytes through the KCNE1 ion channel subunit. Acta Physiol (Oxf) 2010; 198:133-42. [PMID: 19832729 DOI: 10.1111/j.1748-1716.2009.02052.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS The reduced heart rate and prolonged QT(end) duration in mice deficient in thyroid hormone receptor (TR) alpha1 may involve aberrant expression of the K(+) channel alpha-subunit KCNQ1 and its regulatory beta-subunit KCNE1. Here we focus on KCNE1 and study whether increased KCNE1 expression can explain changes in cardiac function observed in TRalpha1-deficient mice. METHODS TR-deficient, KCNE1-overexpressing and their respective wildtype (wt) mice were used. mRNA and protein expression were assessed with Northern and Western blot respectively. Telemetry was used to record electrocardiogram and temperature in freely moving mice. Patch-clamp was used to measure action potentials (APs) in isolated cardiomyocytes and ion currents in Chinese hamster ovary (CHO) cells. RESULTS KCNE1 was four to 10-fold overexpressed in mice deficient in TRalpha1. Overexpression of KCNE1 with a heart-specific promoter in transgenic mice resulted in a cardiac phenotype similar to that in TRalpha1-deficient mice, including a lower heart rate and prolonged QT(end) time. Cardiomyocytes from KCNE1-overexpressing mice displayed increased AP duration. CHO cells transfected with expression plasmids for KCNQ1 and KCNE1 showed an outward rectifying current that was maximal at equimolar plasmids for KCNQ1-KCNE1 and decreased at higher KCNE1 levels. CONCLUSION The bradycardia and prolonged QT(end) time in hypothyroid states can be explained by altered K(+) channel function due to decreased TRalpha1-dependent repression of KCNE1 expression.
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Affiliation(s)
- A Mansén
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
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Rose JB, Naydenova Z, Bang A, Eguchi M, Sweeney G, Choi DS, Hammond JR, Coe IR. Equilibrative nucleoside transporter 1 plays an essential role in cardioprotection. Am J Physiol Heart Circ Physiol 2009; 298:H771-7. [PMID: 20035027 DOI: 10.1152/ajpheart.00711.2009] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
To better understand the role of equilibrative nucleoside transporters (ENT) in purine nucleoside-dependent physiology of the cardiovascular system, we investigated whether the ENT1-null mouse heart was cardioprotected in response to ischemia (coronary occlusion for 30 min followed by reperfusion for 2 h). We observed that ENT1-null mouse hearts showed significantly less myocardial infarction compared with wild-type littermates. We confirmed that isolated wild-type adult mouse cardiomyocytes express predominantly ENT1, which is primarily responsible for purine nucleoside uptake in these cells. However, ENT1-null cardiomyocytes exhibit severely impaired nucleoside transport and lack ENT1 transcript and protein expression. Adenosine receptor expression profiles and expression levels of ENT2, ENT3, and ENT4 were similar in cardiomyocytes isolated from ENT1-null adult mice compared with cardiomyocytes isolated from wild-type littermates. Moreover, small interfering RNA knockdown of ENT1 in the cardiomyocyte cell line, HL-1, mimics findings in ENT1-null cardiomyocytes. Taken together, our data demonstrate that ENT1 plays an essential role in cardioprotection, most likely due to its effects in modulating purine nucleoside-dependent signaling and that the ENT1-null mouse is a powerful model system for the study of the role of ENTs in the physiology of the cardiomyocyte.
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Henson JH, Cheung D, Fried CA, Shuster CB, McClellan MK, Voss MK, Sheridan JT, Oldenbourg R. Structure and dynamics of an Arp2/3 complex-independent component of the lamellipodial actin network. ACTA ACUST UNITED AC 2009; 66:679-92. [PMID: 19530177 DOI: 10.1002/cm.20398] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Sea urchin coelomocytes contain an unusually broad lamellipodial region and have served as a useful model experimental system for studying the process of actin-based retrograde/centripetal flow. In the current study the small molecule drug 2,3-butanedione monoxime (BDM) was employed as a means of delocalizing the Arp2/3 complex from the cell edge in an effort to investigate the Arp2/3 complex-independent aspects of retrograde flow. Digitally-enhanced phase contrast, fluorescence and polarization light microscopy, along with rotary shadow transmission electron microscopy methods demonstrated that BDM treatment resulted in the centripetal displacement of the Arp2/3 complex and the associated dendritic lamellipodial (LP) actin network from the cell edge. In its wake there remained an array of elongate actin filaments organized into concave arcs that displayed retrograde flow at approximately one quarter the normal rate. Actin polymerization inhibitor experiments indicated that these arcs were generated by polymerization at the cell edge, while active myosin-based contraction in BDM treated cells was demonstrated by localization with antiphospho-myosin regulatory light chain (MRLC) antibody, the retraction of the cytoskeleton in the presence of BDM, and the response of the BDM arcs to laser-based severing. The results suggest that BDM treatment reveals an Arp2/3 complex-independent actin structure in coelomocytes consisting of elongate filaments integrated into the LP network and that these filaments represent a potential connection between the LP network and the central cytoskeleton.
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Affiliation(s)
- John H Henson
- Department of Biology, Dickinson College, Carlisle, PA 17013, USA.
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PDK1 coordinates survival pathways and beta-adrenergic response in the heart. Proc Natl Acad Sci U S A 2009; 106:8689-94. [PMID: 19429709 DOI: 10.1073/pnas.0900064106] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The 3-phosphoinositide-dependent kinase-1 (PDK1) plays an important role in the regulation of cellular responses in multiple organs by mediating the phosphoinositide 3-kinase (PI3-K) signaling pathway through activating AGC kinases. Here we defined the role of PDK1 in controlling cardiac homeostasis. Cardiac expression of PDK1 was significantly decreased in murine models of heart failure. Tamoxifen-inducible and heart-specific disruption of Pdk1 in adult mice caused severe and lethal heart failure, which was associated with apoptotic death of cardiomyocytes and beta(1)-adrenergic receptor (AR) down-regulation. Overexpression of Bcl-2 protein prevented cardiomyocyte apoptosis and improved cardiac function. In addition, PDK1-deficient hearts showed enhanced activity of PI3-Kgamma, leading to robust beta(1)-AR internalization by forming complex with beta-AR kinase 1 (betaARK1). Interference of betaARK1/PI3-Kgamma complex formation by transgenic overexpression of phosphoinositide kinase domain normalized beta(1)-AR trafficking and improved cardiac function. Taken together, these results suggest that PDK1 plays a critical role in cardiac homeostasis in vivo by serving as a dual effector for cell survival and beta-adrenergic response.
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Johnston RK, Balasubramanian S, Kasiganesan H, Baicu CF, Zile MR, Kuppuswamy D. Beta3 integrin-mediated ubiquitination activates survival signaling during myocardial hypertrophy. FASEB J 2009; 23:2759-71. [PMID: 19364763 DOI: 10.1096/fj.08-127480] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Identifying the molecular mechanisms activated in compensatory hypertrophy and absent during decompensation will provide molecular targets for prevention of heart failure. We have previously shown enhanced ubiquitination (Ub) during the early growth period of pressure overload (PO) hypertrophy near intercalated discs of cardiomyocytes, where integrins are important for mechanotransduction. In this study, we tested the role of integrins upstream of Ub, whether enhanced Ub contributes to survival signaling in early PO, and if loss of this mechanism could lead to decreased ventricular function. The study used a beta(3) integrin (-/-) mouse and a wild-type mouse as a control for in vivo PO by transverse aortic constriction (TAC) and for cultured cardiomyocytes in vitro, stimulated with the integrin-activating peptide RGD. We demonstrate beta(3) integrin mediates transient Ub of targeted proteins during PO hypertrophy, which is necessary for cardiomyocyte survival and to maintain ventricular function. Prosurvival signaling proceeds by initiation of NF-kappaB transcription of the E3 ligase, cIAP1. In PO beta(3)(-/-) mice, absence of this mechanism correlates with increased TUNEL staining and decreased ventricular mass and function by 4 wk. This is the first study to show that a beta(3) integrin/Ub/NF-kappaB pathway contributes to compensatory hypertrophic growth.
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Affiliation(s)
- Rebecca K Johnston
- Cardiology Division of the Department of Medicine, Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston, South Carolina 29425-2221, USA
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Seewald MJ, Ellinghaus P, Kassner A, Stork I, Barg M, Niebrügge S, Golz S, Summer H, Zweigerdt R, Schräder EM, Feicht S, Jaquet K, Reis S, Körfer R, Milting H. Genomic profiling of developing cardiomyocytes from recombinant murine embryonic stem cells reveals regulation of transcription factor clusters. Physiol Genomics 2009; 38:7-15. [PMID: 19293330 DOI: 10.1152/physiolgenomics.90287.2008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cardiomyocytes derived from pluripotent embryonic stem cells (ESC) have the advantage of providing a source for standardized cell cultures. However, little is known on the regulation of the genome during differentiation of ESC to cardiomyocytes. Here, we characterize the transcriptome of the mouse ESC line CM7/1 during differentiation into beating cardiomyocytes and compare the gene expression profiles with those from primary adult murine cardiomyocytes and left ventricular myocardium. We observe that the cardiac gene expression pattern of fully differentiated CM7/1-ESC is highly similar to adult primary cardiomyocytes and murine myocardium, respectively. This finding is underlined by demonstrating pharmacological effects of catecholamines and endothelin-1 on ESC-derived cardiomyocytes. Furthermore, we monitor the temporal changes in gene expression pattern during ESC differentiation with a special focus on transcription factors involved in cardiomyocyte differentiation. Thus, CM7/1-ESC-derived cardiomyocytes are a promising new tool for functional studies of cardiomyocytes in vitro and for the analysis of the transcription factor network regulating pluripotency and differentiation to cardiomyocytes.
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Affiliation(s)
- Michael J Seewald
- Department of Target Discovery, Bayer Healthcare AG, Wuppertal, Germany
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Defer N, Wan J, Souktani R, Escoubet B, Perier M, Caramelle P, Manin S, Deveaux V, Bourin MC, Zimmer A, Lotersztajn S, Pecker F, Pavoine C. The cannabinoid receptor type 2 promotes cardiac myocyte and fibroblast survival and protects against ischemia/reperfusion-induced cardiomyopathy. FASEB J 2009; 23:2120-30. [PMID: 19246487 DOI: 10.1096/fj.09-129478] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Post-myocardial infarction (MI) heart failure is a major public health problem in Western countries and results from ischemia/reperfusion (IR)-induced cell death, remodeling, and contractile dysfunction. Ex vivo studies have demonstrated the cardioprotective anti-inflammatory effect of the cannabinoid type 2 (CB2) receptor agonists within hours after IR. Herein, we evaluated the in vivo effect of CB2 receptors on IR-induced cell death, fibrosis, and cardiac dysfunction and investigated the target role of cardiac myocytes and fibroblasts. The infarct size was increased 24 h after IR in CB2(-/-) vs. wild-type (WT) hearts and decreased when WT hearts were injected with the CB2 agonist JWH133 (3 mg/kg) at reperfusion. Compared with WT hearts, CB2(-/-) hearts showed widespread injury 3 d after IR, with enhanced apoptosis and remodeling affecting the remote myocardium. Finally, CB2(-/-) hearts exhibited exacerbated fibrosis, associated with left ventricular dysfunction 4 wk after IR, whereas their WT counterparts recovered normal function. Cardiac myocytes and fibroblasts isolated from CB2(-/-) hearts displayed a higher H(2)O(2)-induced death than WT cells, whereas 1 microM JWH133 triggered survival effects. Furthermore, H(2)O(2)-induced myofibroblast activation was increased in CB2(-/-) fibroblasts but decreased in 1 microM JWH133-treated WT fibroblasts, compared with that in WT cells. Therefore, CB2 receptor activation may protect against post-IR heart failure through direct inhibition of cardiac myocyte and fibroblast death and prevention of myofibroblast activation.
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Venkatachalam K, Prabhu SD, Reddy VS, Boylston WH, Valente AJ, Chandrasekar B. Neutralization of interleukin-18 ameliorates ischemia/reperfusion-induced myocardial injury. J Biol Chem 2009; 284:7853-65. [PMID: 19164288 DOI: 10.1074/jbc.m808824200] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Ischemia/reperfusion (I/R) injury is characterized by the induction of oxidative stress and proinflammatory cytokine expression. Recently demonstrating that oxidative stress and TNF-alpha each stimulate interleukin (IL)-18 expression in cardiomyocytes, we hypothesized that I/R also induces IL-18 expression and thus exacerbates inflammation and tissue damage. Neutralization of IL-18 signaling should therefore diminish tissue injury following I/R. I/R studies were performed using a chronically instrumented closed chest mouse model. Male C57BL/6 mice underwent 30 min of ischemia by LAD coronary artery ligation followed by various periods of reperfusion. Sham-operated or ischemia-only mice served as controls. A subset of animals was treated with IL-18-neutralizing antibodies 1 h prior to LAD ligation. Ischemic LV tissue was used for analysis. Our results demonstrate that, compared with sham operation and ischemia alone, I/R significantly increased (i) oxidative stress (increased MDA/4-HNE levels), (ii) neutrophil infiltration (increased MPO activity), (iii) NF-kappaB DNA binding activity (p50, p65), and (iv) increased expression of IL-18Rbeta, but not IL-18Ralpha or IL-18BP transcripts. Administration of IL-18-neutralizing antibodies significantly reduced I/R injury measured by reduced infarct size (versus control IgG). In isolated adult mouse cardiomyocytes, simulated ischemia/reperfusion enhanced oxidative stress and biologically active IL-18 expression via IKK-dependent NF-kappaB activation. These results indicate that IL-18 plays a critical role in I/R injury and thus represents a promising therapeutic target.
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Affiliation(s)
- Kaliyamurthi Venkatachalam
- Department of Veterans Affairs South Texas Veterans Health Care System and the Departments of Medicine and Surgery, University of Texas Health Science Center, San Antonio, Texas 78229, USA
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Li N, Timofeyev V, Tuteja D, Xu D, Lu L, Zhang Q, Zhang Z, Singapuri A, Albert TR, Rajagopal AV, Bond CT, Periasamy M, Adelman J, Chiamvimonvat N. Ablation of a Ca2+-activated K+ channel (SK2 channel) results in action potential prolongation in atrial myocytes and atrial fibrillation. J Physiol 2009; 587:1087-100. [PMID: 19139040 DOI: 10.1113/jphysiol.2008.167718] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Small conductance Ca(2+)-activated K(+) channels (SK channels) have been reported in excitable cells, where they aid in integrating changes in intracellular Ca(2+) (Ca(2+)(i)) with membrane potential. We have recently reported the functional existence of SK2 channels in human and mouse cardiac myocytes. Moreover, we have found that the channel is predominantly expressed in atria compared to the ventricular myocytes. We hypothesize that knockout of SK2 channels may be sufficient to disrupt the intricate balance of the inward and outward currents during repolarization in atrial myocytes. We further predict that knockout of SK2 channels may predispose the atria to tachy-arrhythmias due to the fact that the late phase of the cardiac action potential is highly susceptible to aberrant excitation. We take advantage of a mouse model with genetic knockout of the SK2 channel gene. In vivo and in vitro electrophysiological studies were performed to probe the functional roles of SK2 channels in the heart. Whole-cell patch-clamp techniques show a significant prolongation of the action potential duration prominently in late cardiac repolarization in atrial myocytes from the heterozygous and homozygous null mutant animals. Moreover, in vivo electrophysiological recordings show inducible atrial fibrillation in the null mutant mice but not wild-type animals. No ventricular arrhythmias are detected in the null mutant mice or wild-type animals. In summary, our data support the important functional roles of SK2 channels in cardiac repolarization in atrial myocytes. Genetic knockout of the SK2 channels results in the delay in cardiac repolarization and atrial arrhythmias.
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Affiliation(s)
- Ning Li
- Division of Cardiovascular Medicine, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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Caglayan E, Stauber B, Collins AR, Lyon CJ, Yin F, Liu J, Rosenkranz S, Erdmann E, Peterson LE, Ross RS, Tangirala RK, Hsueh WA. Differential roles of cardiomyocyte and macrophage peroxisome proliferator-activated receptor gamma in cardiac fibrosis. Diabetes 2008; 57:2470-9. [PMID: 18511847 PMCID: PMC2518499 DOI: 10.2337/db07-0924] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Accepted: 05/14/2008] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Cardiac fibrosis is an important component of diabetic cardiomyopathy. Peroxisome proliferator-activated receptor gamma (PPARgamma) ligands repress proinflammatory gene expression, including that of osteopontin, a known contributor to the development of myocardial fibrosis. We thus investigated the hypothesis that PPARgamma ligands could attenuate cardiac fibrosis. RESEARCH DESIGN AND METHODS Wild-type cardiomyocyte- and macrophage-specific PPARgamma(-/-) mice were infused with angiotensin II (AngII) to promote cardiac fibrosis and treated with the PPARgamma ligand pioglitazone to determine the roles of cardiomyocyte and macrophage PPARgamma in cardiac fibrosis. RESULTS Cardiomyocyte-specific PPARgamma(-/-) mice (cPPARgamma(-/-)) developed spontaneous cardiac hypertrophy with increased ventricular osteopontin expression and macrophage content, which were exacerbated by AngII infusion. Pioglitazone attenuated AngII-induced fibrosis, macrophage accumulation, and osteopontin expression in both wild-type and cPPARgamma(-/-) mice but induced hypertrophy in a PPARgamma-dependent manner. We pursued two mechanisms to explain the antifibrotic cardiomyocyte-PPARgamma-independent effects of pioglitazone: increased adiponectin expression and attenuation of proinflammatory macrophage activity. Adenovirus-expressed adiponectin had no effect on cardiac fibrosis and the PPARgamma ligand pioglitazone did not attenuate AngII-induced cardiac fibrosis, osteopontin expression, or macrophage accumulation in monocyte-specific PPARgamma(-/-) mice. CONCLUSIONS We arrived at the following conclusions: 1) both cardiomyocyte-specific PPARgamma deficiency and activation promote cardiac hypertrophy, 2) both cardiomyocyte and monocyte PPARgamma regulate cardiac macrophage infiltration, 3) inflammation is a key mediator of AngII-induced cardiac fibrosis, 4) macrophage PPARgamma activation prevents myocardial macrophage accumulation, and 5) PPARgamma ligands attenuate AngII-induced cardiac fibrosis by inhibiting myocardial macrophage infiltration. These observations have important implications for potential interventions to prevent cardiac fibrosis.
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Affiliation(s)
- Evren Caglayan
- Division of Endocrinology, Diabetes and Hypertension, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
- Klinik III für Innere Medizin, Universität zu Köln, Köln, Germany
| | - Bradley Stauber
- Division of Endocrinology, Diabetes and Hypertension, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Alan R. Collins
- Division of Diabetes, Obesity and Lipids, The Methodist Hospital Research Institute, Houston, Texas
| | - Christopher J. Lyon
- Division of Diabetes, Obesity and Lipids, The Methodist Hospital Research Institute, Houston, Texas
| | - Fen Yin
- Division of Endocrinology, Diabetes and Hypertension, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Joey Liu
- Division of Diabetes, Obesity and Lipids, The Methodist Hospital Research Institute, Houston, Texas
| | | | - Erland Erdmann
- Klinik III für Innere Medizin, Universität zu Köln, Köln, Germany
| | - Leif E. Peterson
- Center for Biostatistics, The Methodist Hospital Research Institute, Houston, Texas
| | - Robert S. Ross
- Division of Cardiology, Department of Medicine, Veterans Affairs Medical Center and University of California, San Diego, San Diego, California
| | - Rajendra K. Tangirala
- Division of Endocrinology, Diabetes and Hypertension, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Willa A. Hsueh
- Division of Diabetes, Obesity and Lipids, The Methodist Hospital Research Institute, Houston, Texas
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Rizzi N, Liu N, Napolitano C, Nori A, Turcato F, Colombi B, Bicciato S, Arcelli D, Spedito A, Scelsi M, Villani L, Esposito G, Boncompagni S, Protasi F, Volpe P, Priori SG. Unexpected structural and functional consequences of the R33Q homozygous mutation in cardiac calsequestrin: a complex arrhythmogenic cascade in a knock in mouse model. Circ Res 2008; 103:298-306. [PMID: 18583715 DOI: 10.1161/circresaha.108.171660] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmogenic disorder characterized by life threatening arrhythmias elicited by physical and emotional stress in young individuals. The recessive form of CPVT is associated with mutation in the cardiac calsequestrin gene (CASQ2). We engineered and characterized a homozygous CASQ2(R33Q/R33Q) mouse model that closely mimics the clinical phenotype of CPVT patients. CASQ2(R33Q/R33Q) mice develop bidirectional VT on exposure to environmental stress whereas CASQ2(R33Q/R33Q) myocytes show reduction of the sarcoplasmic reticulum (SR) calcium content, adrenergically mediated delayed (DADs) and early (EADs) afterdepolarizations leading to triggered activity. Furthermore triadin, junctin, and CASQ2-R33Q proteins are significantly decreased in knock-in mice despite normal levels of mRNA, whereas the ryanodine receptor (RyR2), calreticulin, phospholamban, and SERCA2a-ATPase are not changed. Trypsin digestion studies show increased susceptibility to proteolysis of mutant CASQ2. Despite normal histology, CASQ2(R33Q/R33Q) hearts display ultrastructural changes such as disarray of junctional electron-dense material, referable to CASQ2 polymers, dilatation of junctional SR, yet normal total SR volume. Based on the foregoings, we propose that the phenotype of the CASQ2(R33Q/R33Q) CPVT mouse model is portrayed by an unexpected set of abnormalities including (1) reduced CASQ2 content, possibly attributable to increased degradation of CASQ2-R33Q, (2) reduction of SR calcium content, (3) dilatation of junctional SR, and (4) impaired clustering of mutant CASQ2.
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Affiliation(s)
- Nicoletta Rizzi
- Molecular Cardiology, IRCCS Maugeri Foundation, Pavia, Italy
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Werdich AA, Lima EA, Dzhura I, Singh MV, Li J, Anderson ME, Baudenbacher FJ. Differential effects of phospholamban and Ca2+/calmodulin-dependent kinase II on [Ca2+]i transients in cardiac myocytes at physiological stimulation frequencies. Am J Physiol Heart Circ Physiol 2008; 294:H2352-62. [PMID: 18359893 DOI: 10.1152/ajpheart.01398.2006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In cardiac myocytes, the activity of the Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is hypothesized to regulate Ca(2+) release from and Ca(2+) uptake into the sarcoplasmic reticulum via the phosphorylation of the ryanodine receptor 2 and phospholamban (PLN), respectively. We tested the role of CaMKII and PLN on the frequency adaptation of cytosolic Ca(2+) concentration ([Ca(2+)](i)) transients in nearly 500 isolated cardiac myocytes from transgenic mice chronically expressing a specific CaMKII inhibitor, interbred into wild-type or PLN null backgrounds under physiologically relevant pacing conditions (frequencies from 0.2 to 10 Hz and at 37 degrees C). When compared with that of mice lacking PLN only, the combined chronic CaMKII inhibition and PLN ablation decreased the maximum Ca(2+) release rate by more than 50% at 10 Hz. Although PLN ablation increased the rate of Ca(2+) uptake at all frequencies, its combination with CaMKII inhibition did not prevent a frequency-dependent reduction of the amplitude and the duration of the [Ca(2+)](i) transient. High stimulation frequencies in the physiological range diminished the effects of PLN ablation on the decay time constant and on the maximum decay rate of the [Ca(2+)](i) transient, indicating that the PLN-mediated feedback on [Ca(2+)](i) removal is limited by high stimulation frequencies. Taken together, our results suggest that in isolated mouse ventricular cardiac myocytes, the combined chronic CaMKII inhibition and PLN ablation slowed Ca(2+) release at physiological frequencies: the frequency-dependent decay of the amplitude and shortening of the [Ca(2+)](i) transient occurs independent of chronic CaMKII inhibition and PLN ablation, and the PLN-mediated regulation of Ca(2+) uptake is diminished at higher stimulation frequencies within the physiological range.
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Affiliation(s)
- Andreas A Werdich
- Department of Biomedical Engineering, Vanderbilt University, 6301 Stevenson Center, VU Station B 351631, Nashville, TN 37235-1631, USA
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Kabaeva Z, Zhao M, Michele DE. Blebbistatin extends culture life of adult mouse cardiac myocytes and allows efficient and stable transgene expression. Am J Physiol Heart Circ Physiol 2008; 294:H1667-74. [PMID: 18296569 DOI: 10.1152/ajpheart.01144.2007] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The characterization of cellular phenotypes of heart disorders can be achieved by isolating cardiac myocytes from mouse models or genetically modifying wild-type cells in culture. However, adult mouse cardiac myocytes show extremely low tolerance to isolation and primary culture conditions. Previous studies indicate that 2,3-butanedione monoximine (BDM), a nonspecific excitation-contraction coupling inhibitor, can improve the viability of isolated adult mouse cardiac myocytes. The mechanisms of the beneficial and unwanted nonspecific actions of BDM on cardiac myocytes are not understood. To understand what contributes to murine adult cardiac myocyte stability in primary culture and improve this model system for experimental use, the specific myosin II inhibitor blebbistatin was explored as a media supplement to inhibit mouse myocyte contraction. Enzymatically isolated adult mouse cardiac myocytes were cultured with blebbistatin or BDM as a media supplement. Micromolar concentrations of blebbistatin significantly increased the viability, membrane integrity, and morphology of adult cardiac myocytes compared with cells treated with previously described 10 mM BDM. Cells treated with blebbistatin also showed efficient adenovirus gene transfer and stable transgene expression, and unlike BDM, blebbistatin does not appear to interfere with cell adhesion. Higher concentrations of BDM actually worsened myocyte membrane integrity and transgene expression. Therefore, the specific inhibition of myosin II activity by blebbistatin has significant beneficial effects on the long-term viability of adult mouse cardiac myocytes. Furthermore, the unwanted effects of BDM on adult mouse cardiac myocytes, perhaps due to its nonspecific activities or action as a chemical phosphatase, can be avoided by using blebbistatin.
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Affiliation(s)
- Zhyldyz Kabaeva
- Dept. of Molecular and Integrative Physiology, University of Michigan, 7623A Medical Science II, Ann Arbor, MI 48109-0622, USA
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36
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Viero C, Kraushaar U, Ruppenthal S, Kaestner L, Lipp P. A primary culture system for sustained expression of a calcium sensor in preserved adult rat ventricular myocytes. Cell Calcium 2008; 43:59-71. [PMID: 17822759 DOI: 10.1016/j.ceca.2007.04.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 03/27/2007] [Indexed: 11/21/2022]
Abstract
For studying heart pathologies on the cellular level, cultured adult cardiac myocytes represent an important approach. We aimed to explore a novel adult rat ventricular myocyte culture system with minimised dedifferentiation allowing extended experimental manipulation of the cells such as expression of exogenous proteins. Various culture conditions were investigated including medium supplement, substrate coating and electrical pacing for one week. Adult myocytes were probed for (i) viability, (ii) morphology, (iii) frequency dependence of contractions, (iv) Ca(2+) transients, and (v) their tolerance towards adenovirus-mediated expression of the Ca(2+) sensor "inverse pericam". Conventionally, in either serum supplemented or serum-free medium, myocytes dedifferentiated into flat cells within 3 days or cell physiology and morphology were impaired, respectively. In contrast, myocytes cultured in medium supplemented with an insulin-transferrin-selenite mixture on substrates coated with extracellular matrix proteins showed an increased cell attachment and a conserved cross-striation. Moreover, these myocytes displayed optimised preservation of their contractile behaviour and Ca(2+) signalling even under conditions of continuous electrical pacing. Sustained expression of inverse pericam did not alter myocyte function and allowed long lasting high speed Ca(2+) imaging of electrically driven adult myocytes. Our single-cell model thus provides a new advance for high-content screening of these highly specialised cells.
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Affiliation(s)
- Cedric Viero
- Institute for Molecular Cell Biology, Medical Faculty, Saarland University, Building 61, 66421 Homburg/Saar, Germany
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37
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Sag CM, Dybkova N, Neef S, Maier LS. Effects on recovery during acidosis in cardiac myocytes overexpressing CaMKII. J Mol Cell Cardiol 2007; 43:696-709. [DOI: 10.1016/j.yjmcc.2007.09.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Revised: 09/07/2007] [Accepted: 09/20/2007] [Indexed: 10/22/2022]
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39
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Shioya T. A simple technique for isolating healthy heart cells from mouse models. J Physiol Sci 2007; 57:327-35. [PMID: 17980092 DOI: 10.2170/physiolsci.rp010107] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Accepted: 11/02/2007] [Indexed: 11/05/2022]
Abstract
Single heart cells of mouse models provide powerful tools for heart research. However, their isolation is not easy, and it imposes a significant bottleneck on their use in cellular studies of the heart. Aiming to overcome this problem, this report introduces a novel technique that reproducibly isolates healthy heart cells from mouse models. Using simple devices that ensure easy handling and the rapid aortic cannulation of a small mouse heart, cell isolation was done under physiological conditions without using the "KB" medium or 2,3-butanedione monoxime (BDM). The isolated cells consistently had a healthy appearance and a high viability of 75 +/- 5% (mean +/- SD) in Tyrode solution containing 1.8 mM Ca2+. After 8 h of storage at 37 degrees C, they still had a viability of 45 +/- 12%. The cells showed normal contraction properties when field-stimulated, and they generated normal action potentials and membrane currents under the whole-cell clamp condition. The beta-adrenergic signal transduction of the cells was also normal when it was examined with the isoproterenol enhancement of the L-type Ca2+ current.
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Affiliation(s)
- Takao Shioya
- Department of Physiology, Faculty of Medicine, Saga University, Saga 849-8501, Japan.
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40
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Luo J, Hill BG, Gu Y, Cai J, Srivastava S, Bhatnagar A, Prabhu SD. Mechanisms of acrolein-induced myocardial dysfunction: implications for environmental and endogenous aldehyde exposure. Am J Physiol Heart Circ Physiol 2007; 293:H3673-84. [PMID: 17921335 DOI: 10.1152/ajpheart.00284.2007] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aldehydes are ubiquitous pollutants generated during the combustion of organic materials and are present in air, water, and food. Several aldehydes are also endogenous products of lipid peroxidation and by-products of drug metabolism. Despite well-documented high reactivity of unsaturated aldehydes, little is known regarding their cardiovascular effects and their role in cardiac pathology. Accordingly, we examined the myocardial effects of the model unsaturated aldehyde acrolein. In closed-chest mice, intravenous acrolein (0.5 mg/kg) induced rapid but reversible left ventricular dilatation and dysfunction. In mouse myocytes, micromolar acrolein acutely depressed myofilament Ca(2+) responsiveness without altering catecholamine sensitivity, similar to the phenotype of stunned myocardium. Immunoblotting revealed increased acrolein-protein adducts and protein-carbonyls in both acrolein-exposed myocardium (1.8-fold increase, P < 0.002) and myocytes (6.4-fold increase, P < 0.02). Both the contractile dysfunction and adduct formation were markedly attenuated by pretreatment with the thiol donor N-acetylcysteine (5 mM). Two-dimensional gel electrophoresis and mass-assisted laser desorption/ionization time-of-flight mass spectrometry analysis revealed two groups of adducted proteins, sarcomeric/cytoskeletal proteins (cardiac alpha-actin, desmin, myosin light polypeptide 3) and energy metabolism proteins (mitochondrial creatine kinase-2, ATP synthase), indicating site-specific protein modification that was confirmed by immunohistochemical colocalization. We conclude that direct exposure to acrolein induces selective myofilament impairment, which may be, in part, related to the modification of proteins involved in myocardial contraction and energy metabolism. Myocardial dysfunction induced by acrolein and related aldehydes may be symptomatic of toxicological states associated with ambient or occupational exposures or drug toxicity. Moreover, aldehydes such as acrolein may mediate cardiac dysfunction in pathologies characterized by high-oxidative stress.
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Affiliation(s)
- Jianzhu Luo
- Institute of Molecular Cardiology, Department of Medicine, University of Louisville, 550 South Jackson Street, Louisville, KY 40202, USA
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41
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Boerries M, Most P, Gledhill JR, Walker JE, Katus HA, Koch WJ, Aebi U, Schoenenberger CA. Ca2+ -dependent interaction of S100A1 with F1-ATPase leads to an increased ATP content in cardiomyocytes. Mol Cell Biol 2007; 27:4365-73. [PMID: 17438143 PMCID: PMC1900044 DOI: 10.1128/mcb.02045-06] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
S100A1, a Ca(2+)-sensing protein of the EF-hand family that is expressed predominantly in cardiac muscle, plays a pivotal role in cardiac contractility in vitro and in vivo. It has recently been demonstrated that by restoring Ca(2+) homeostasis, S100A1 was able to rescue contractile dysfunction in failing rat hearts. Myocardial contractility is regulated not only by Ca(2+) homeostasis but also by energy metabolism, in particular the production of ATP. Here, we report a novel interaction of S100A1 with mitochondrial F(1)-ATPase, which affects F(1)-ATPase activity and cellular ATP production. In particular, cardiomyocytes that overexpress S100A1 exhibited a higher ATP content than control cells, whereas knockdown of S100A1 expression decreased ATP levels. In pull-down experiments, we identified the alpha- and beta-chain of F(1)-ATPase to interact with S100A1 in a Ca(2+)-dependent manner. The interaction was confirmed by colocalization studies of S100A1 and F(1)-ATPase and the analysis of the S100A1-F(1)-ATPase complex by gel filtration chromatography. The functional impact of this association is highlighted by an S100A1-mediated increase of F(1)-ATPase activity. Consistently, ATP synthase activity is reduced in cardiomyocytes from S100A1 knockout mice. Our data indicate that S100A1 might play a key role in cardiac energy metabolism.
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MESH Headings
- Adenosine Triphosphate/analysis
- Adenoviridae/genetics
- Animals
- Calcium/metabolism
- Cells, Cultured
- Fluorescent Antibody Technique, Indirect
- Genes, Reporter
- Glutathione Transferase/metabolism
- Green Fluorescent Proteins/metabolism
- Heart Ventricles/cytology
- Luciferases/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mitochondria, Heart/enzymology
- Mitochondria, Heart/metabolism
- Mitochondria, Heart/ultrastructure
- Myocytes, Cardiac/chemistry
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/ultrastructure
- Proton-Translocating ATPases/genetics
- Proton-Translocating ATPases/isolation & purification
- Proton-Translocating ATPases/metabolism
- Proton-Translocating ATPases/ultrastructure
- RNA Interference
- Recombinant Fusion Proteins/isolation & purification
- Recombinant Fusion Proteins/metabolism
- S100 Proteins/genetics
- S100 Proteins/isolation & purification
- S100 Proteins/metabolism
- S100 Proteins/ultrastructure
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Affiliation(s)
- Melanie Boerries
- Maurice E Mueller Institute for Structural Biology, Biozentrum, University of Basel, Basel, Switzerland
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42
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Fauconnier J, Andersson DC, Zhang SJ, Lanner JT, Wibom R, Katz A, Bruton JD, Westerblad H. Effects of palmitate on Ca(2+) handling in adult control and ob/ob cardiomyocytes: impact of mitochondrial reactive oxygen species. Diabetes 2007; 56:1136-42. [PMID: 17229941 DOI: 10.2337/db06-0739] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Obesity and insulin resistance are associated with enhanced fatty acid utilization, which may play a central role in diabetic cardiomyopathy. We now assess the effect of the saturated fatty acid palmitate (1.2 mmol/l) on Ca(2+) handling, cell shortening, and mitochondrial production of reactive oxygen species (ROS) in freshly isolated ventricular cardiomyocytes from normal (wild-type) and obese, insulin-resistant ob/ob mice. Cardiomyocytes were electrically stimulated at 1 Hz, and the signal of fluorescent indicators was measured with confocal microscopy. Palmitate decreased the amplitude of cytosolic Ca(2+) transients (measured with fluo-3), the sarcoplasmic reticulum Ca(2+) load, and cell shortening by approximately 20% in wild-type cardiomyocytes; these decreases were prevented by the general antioxidant N-acetylcysteine. In contrast, palmitate accelerated Ca(2+) transients and increased cell shortening in ob/ob cardiomyocytes. Application of palmitate rapidly dissipated the mitochondrial membrane potential (measured with tetra-methyl rhodamine-ethyl ester) and increased the mitochondrial ROS production (measured with MitoSOX Red) in wild-type but not in ob/ob cardiomyocytes. In conclusion, increased saturated fatty acid levels impair cellular Ca(2+) handling and contraction in a ROS-dependent manner in normal cardiomyocytes. Conversely, high fatty acid levels may be vital to sustain cardiac Ca(2+) handling and contraction in obesity and insulin-resistant conditions.
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Affiliation(s)
- Jérémy Fauconnier
- Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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43
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Werdich AA, Baudenbacher F, Dzhura I, Jeyakumar LH, Kannankeril PJ, Fleischer S, LeGrone A, Milatovic D, Aschner M, Strauss AW, Anderson ME, Exil VJ. Polymorphic ventricular tachycardia and abnormal Ca2+ handling in very-long-chain acyl-CoA dehydrogenase null mice. Am J Physiol Heart Circ Physiol 2007; 292:H2202-11. [PMID: 17209005 DOI: 10.1152/ajpheart.00382.2006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Patients with mutations in the mitochondrial very-long-chain acyl-CoA dehydrogenase (VLCAD) gene are at risk for cardiomyopathy, myocardial dysfunction, ventricular tachycardia (VT), and sudden cardiac death. The mechanism is not known. Here we report a novel mechanism of VT in mice lacking VLCAD (VLCAD(-/-)). These mice exhibited polymorphic VT and increased incidence of VT after isoproterenol infusion. Polymorphic VT was induced in 10 out of 12 VLCAD(-/-) mice (83%) when isoproterenol was used. One out of 10 VLCAD(-/-) mice with polymorphic VT had VT with the typical bidirectional morphology. At the molecular level, VLCAD(-/-) cardiomyocytes showed increased levels of cardiac ryanodine receptor 2, phospholamban, and calsequestrin with increased [(3)H]ryanodine binding in heart microsomes. At the single cardiomyocyte level, VLCAD(-/-) cardiomyocytes showed significant increase in diastolic indo 1 and fura 2 fluorescence, with increased Ca(2+) transient amplitude. These changes were associated with altered Ca(2+) dynamics, to include: faster sarcomere contraction, larger time derivative of the upstroke, and shorter time-to-minimum sarcomere length compared with VLCAD(+/+) control cells. The L-type Ca(2+) current characteristics were not different under voltage-clamp conditions in the two VLCAD genotypes. Sarcoplasmic reticulum Ca(2+) load measured as normalized integrated Na(+)/Ca(2+) exchange current after rapid caffeine application was increased by 48% in VLCAD(-/-) cells. We conclude that intracellular Ca(2+) handling represents a possible molecular mechanism of arrhythmias in mice and perhaps in VLCAD-deficient humans.
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Affiliation(s)
- Andreas A Werdich
- Division of Cardiology, Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232-0001, USA
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44
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McMullen JR, Amirahmadi F, Woodcock EA, Schinke-Braun M, Bouwman RD, Hewitt KA, Mollica JP, Zhang L, Zhang Y, Shioi T, Buerger A, Izumo S, Jay PY, Jennings GL. Protective effects of exercise and phosphoinositide 3-kinase(p110alpha) signaling in dilated and hypertrophic cardiomyopathy. Proc Natl Acad Sci U S A 2007; 104:612-7. [PMID: 17202264 PMCID: PMC1766433 DOI: 10.1073/pnas.0606663104] [Citation(s) in RCA: 231] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Physical activity protects against cardiovascular disease, and physiological cardiac hypertrophy associated with regular exercise is usually beneficial, in marked contrast to pathological hypertrophy associated with disease. The p110alpha isoform of phosphoinositide 3-kinase (PI3K) plays a critical role in the induction of exercise-induced hypertrophy. Whether it or other genes activated in the athlete's heart might have an impact on cardiac function and survival in a setting of heart failure is unknown. To examine whether progressive exercise training and PI3K(p110alpha) activity affect survival and/or cardiac function in two models of heart disease, we subjected a transgenic mouse model of dilated cardiomyopathy (DCM) to swim training, genetically crossed cardiac-specific transgenic mice with increased or decreased PI3K(p110alpha) activity to the DCM model, and subjected PI3K(p110alpha) transgenics to acute pressure overload (ascending aortic constriction). Life-span, cardiac function, and molecular markers of pathological hypertrophy were examined. Exercise training and increased cardiac PI3K(p110alpha) activity prolonged survival in the DCM model by 15-20%. In contrast, reduced PI3K(p110alpha) activity drastically shortened lifespan by approximately 50%. Increased PI3K(p110alpha) activity had a favorable effect on cardiac function and fibrosis in the pressure-overload model and attenuated pathological growth. PI3K(p110alpha) signaling negatively regulated G protein-coupled receptor stimulated extracellular responsive kinase and Akt (via PI3K, p110gamma) activation in isolated cardiomyocytes. These findings suggest that exercise and enhanced PI3K(p110alpha) activity delay or prevent progression of heart disease, and that supraphysiologic activity can be beneficial. Identification of genes important for hypertrophy in the athlete's heart could offer new strategies for treating heart failure.
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MESH Headings
- Animals
- Cardiomyopathy, Dilated/pathology
- Cardiomyopathy, Dilated/physiopathology
- Cardiomyopathy, Dilated/prevention & control
- Cardiomyopathy, Hypertrophic/pathology
- Cardiomyopathy, Hypertrophic/physiopathology
- Cardiomyopathy, Hypertrophic/prevention & control
- Class I Phosphatidylinositol 3-Kinases
- Disease Models, Animal
- Female
- Gene Expression
- Humans
- Male
- Mice
- Mice, Knockout
- Mice, Transgenic
- Phosphatidylinositol 3-Kinases/deficiency
- Phosphatidylinositol 3-Kinases/genetics
- Phosphatidylinositol 3-Kinases/metabolism
- Physical Conditioning, Animal
- Physical Exertion/physiology
- Signal Transduction
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Affiliation(s)
- Julie R McMullen
- Experimental Cardiology and Heart Failure Division, Baker Heart Research Institute, Melbourne 8008, Australia.
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45
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Huang KS, Lin YC, Su CC, Fang CS. Enhancement of an electroporation system for gene delivery using electrophoresis with a planar electrode. LAB ON A CHIP 2007; 7:86-92. [PMID: 17180209 DOI: 10.1039/b613753a] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
In this paper a new electroporation (EP) system is developed, which includes an EP microchip and a logic circuit, which combined with electrophoresis (ES), can provide site-specific enhancement of gene concentration. In this ES-EP microchip, an arc planar electrode provides the ES function for DNA attraction, and interdigitated array electrodes provide appropriate electric fields for the EP on the chip surface. In addition, the adherent cells can be manipulated in situ without detachment of the ES-EP microchip, which performs the "Lab on a chip". Experimental results have shown that the efficiency of gene transfection with an attracting-electric field (35.89%) becomes much higher than that without an attracting-electric field (16.62%). Cell numbers as low as 10(4) cells, and DNA as little as 4 microg are sufficient for evaluating the phenotypic effects following the over-expression of the introduced genes on the ES-EP microchip. The proposed system has the advantages of portability, cost-effectiveness, a high transfection rate and ease of operation.
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Affiliation(s)
- Keng-Shiang Huang
- Department of Engineering Science, National Cheng Kung University, 1 University Road, 701 Tainan, Taiwan, R.O.C
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46
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Lau JMC, Jin X, Ren J, Avery J, DeBosch BJ, Treskov I, Lupu TS, Kovacs A, Weinheimer C, Muslin AJ. The 14-3-3tau phosphoserine-binding protein is required for cardiomyocyte survival. Mol Cell Biol 2006; 27:1455-66. [PMID: 17145769 PMCID: PMC1800730 DOI: 10.1128/mcb.01369-06] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
14-3-3 family members are intracellular dimeric phosphoserine-binding proteins that regulate signal transduction, cell cycle, apoptotic, and metabolic cascades. Previous work with global 14-3-3 protein inhibitors suggested that these proteins play a critical role in antagonizing apoptotic cell death in response to provocative stimuli. To determine the specific role of one family member in apoptosis, mice were generated with targeted disruption of the 14-3-3tau gene. 14-3-3tau(-/-) mice did not survive embryonic development, but haploinsufficient mice appeared normal at birth and were fertile. Cultured adult cardiomyocytes derived from 14-3-3tau(+/-) mice were sensitized to apoptosis in response to hydrogen peroxide or UV irradiation. 14-3-3tau(+/-) mice were intolerant of experimental myocardial infarction and developed pathological ventricular remodeling with increased cardiomyocyte apoptosis. ASK1, c-jun NH(2)-terminal kinase, and p38 mitogen-activated protein kinase (MAPK) activation was increased, but extracellular signal-regulated kinase MAPK activation was reduced, in 14-3-3tau(+/-) cardiac tissue. Inhibition of p38 MAPK increased survival in 14-3-3tau(+/-) mice subjected to myocardial infarction. These results demonstrate that 14-3-3tau plays a critical antiapoptotic function in cardiomyocytes and that therapeutic agents that increase 14-3-3tau activity may be beneficial to patients with myocardial infarction.
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Affiliation(s)
- Jeffrey M C Lau
- Center for Cardiovascular Research, Washington University School of Medicine, 660 South Euclid Ave., St. Louis, MO 63110, USA
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47
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Alvarez BV, Johnson DE, Sowah D, Soliman D, Light PE, Xia Y, Karmazyn M, Casey JR. Carbonic anhydrase inhibition prevents and reverts cardiomyocyte hypertrophy. J Physiol 2006; 579:127-45. [PMID: 17124262 PMCID: PMC2075384 DOI: 10.1113/jphysiol.2006.123638] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Hypertrophic cardiomyocyte growth contributes substantially to the progression of heart failure. Activation of the plasma membrane Na+-H+ exchanger (NHE1) and Cl- -HCO3- exchanger (AE3) has emerged as a central point in the hypertrophic cascade. Both NHE1 and AE3 bind carbonic anhydrase (CA), which activates their transport flux, by providing H+ and HCO3-, their respective transport substrates. We examined the contribution of CA activity to the hypertrophic response of cultured neonatal and adult rodent cardiomyocytes. Phenylephrine (PE) increased cell size by 37 +/- 2% and increased expression of the hypertrophic marker, atrial natriuretic factor mRNA, twofold in cultured neonatal rat cardiomyocytes. Cell size was also increased in adult cardiomyocytes subjected to angiotensin II or PE treatment. These effects were associated with increased expression of cytosolic CAII protein and the membrane-anchored isoform, CAIV. The membrane-permeant CA inhibitor, 6-ethoxyzolamide (ETZ), both prevented and reversed PE-induced hypertrophy in a concentration-dependent manner in neonate cardiomyocytes (IC50=18 microm). ETZ and the related CA inhibitor methazolamide prevented hypertrophy in adult cardiomyocytes. In addition, ETZ inhibited transport activity of NHE1 and the AE isoform, AE3, with respective EC50 values of 1.2 +/- 0.3 microm and 2.7 +/- 0.3 microm. PE significantly increased neonatal cardiomyocyte Ca2+ transient frequency from 0.33 +/- 0.4 Hz to 0.77 +/- 0.04 Hz following 24 h treatment; these Ca2+ -handling abnormalities were completely prevented by ETZ (0.28 +/- 0.07 Hz). Our study demonstrates a novel role for CA in mediating the hypertrophic response of cardiac myocytes to PE and suggests that CA inhibition represents an effective therapeutic approach towards mitigation of the hypertrophic phenotype.
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Affiliation(s)
- Bernardo V Alvarez
- Department of Physiology, Membrane Protein Research Group, University of Alberta, Edmonton, Canada T6G2H7
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48
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DeBosch B, Sambandam N, Weinheimer C, Courtois M, Muslin AJ. Akt2 regulates cardiac metabolism and cardiomyocyte survival. J Biol Chem 2006; 281:32841-51. [PMID: 16950770 PMCID: PMC2724003 DOI: 10.1074/jbc.m513087200] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The Akt family of serine-threonine kinases participates in diverse cellular processes, including the promotion of cell survival, glucose metabolism, and cellular protein synthesis. All three known Akt family members, Akt1, Akt2 and Akt3, are expressed in the myocardium, although Akt1 and Akt2 are most abundant. Previous studies demonstrated that Akt1 and Akt3 overexpression results in enhanced myocardial size and function. Yet, little is known about the role of Akt2 in modulating cardiac metabolism, survival, and growth. Here, we utilize murine models with targeted disruption of the akt2 or the akt1 genes to demonstrate that Akt2, but not Akt1, is required for insulin-stimulated 2-[(3)H]deoxyglucose uptake and metabolism. In contrast, akt2(-/-) mice displayed normal cardiac growth responses to provocative stimulation, including ligand stimulation of cultured cardiomyocytes, pressure overload by transverse aortic constriction, and myocardial infarction. However, akt2(-/-) mice were found to be sensitized to cardiomyocyte apoptosis in response to ischemic injury, and apoptosis was significantly increased in the peri-infarct zone of akt2(-/-) hearts 7 days after occlusion of the left coronary artery. These results implicate Akt2 in the regulation of cardiomyocyte metabolism and survival.
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Affiliation(s)
- Brian DeBosch
- Center for Cardiovascular Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Nandakumar Sambandam
- Center for Cardiovascular Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Carla Weinheimer
- Center for Cardiovascular Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Michael Courtois
- Center for Cardiovascular Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Anthony J. Muslin
- Center for Cardiovascular Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110
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49
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Kannankeril PJ, Mitchell BM, Goonasekera SA, Chelu MG, Zhang W, Sood S, Kearney DL, Danila CI, De Biasi M, Wehrens XHT, Pautler RG, Roden DM, Taffet GE, Dirksen RT, Anderson ME, Hamilton SL. Mice with the R176Q cardiac ryanodine receptor mutation exhibit catecholamine-induced ventricular tachycardia and cardiomyopathy. Proc Natl Acad Sci U S A 2006; 103:12179-84. [PMID: 16873551 PMCID: PMC1567715 DOI: 10.1073/pnas.0600268103] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mutations in the cardiac ryanodine receptor 2 (RyR2) have been associated with catecholaminergic polymorphic ventricular tachycardia and a form of arrhythmogenic right ventricular dysplasia. To study the relationship between RyR2 function and these phenotypes, we developed knockin mice with the human disease-associated RyR2 mutation R176Q. Histologic analysis of hearts from RyR2(R176Q/+) mice revealed no evidence of fibrofatty infiltration or structural abnormalities characteristic of arrhythmogenic right ventricular dysplasia, but right ventricular end-diastolic volume was decreased in RyR2(R176Q/+) mice compared with controls, indicating subtle functional impairment due to the presence of a single mutant allele. Ventricular tachycardia (VT) was observed after caffeine and epinephrine injection in RyR2(R176Q/+), but not in WT, mice. Intracardiac electrophysiology studies with programmed stimulation also elicited VT in RyR2(R176Q/+) mice. Isoproterenol administration during programmed stimulation increased both the number and duration of VT episodes in RyR2(R176Q/+) mice, but not in controls. Isolated cardiomyocytes from RyR2(R176Q/+) mice exhibited a higher incidence of spontaneous Ca(2+) oscillations in the absence and presence of isoproterenol compared with controls. Our results suggest that the R176Q mutation in RyR2 predisposes the heart to catecholamine-induced oscillatory calcium-release events that trigger a calcium-dependent ventricular arrhythmia.
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Affiliation(s)
| | | | - Sanjeewa A. Goonasekera
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14627; and
| | | | - Wei Zhang
- Medicine and Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Subeena Sood
- Departments of Molecular Physiology and Biophysics
| | | | | | - Mariella De Biasi
- Departments of Medicine and Physiology and Biophysics, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242
| | - Xander H. T. Wehrens
- Departments of Molecular Physiology and Biophysics
- Medicine, Baylor College of Medicine, Houston, TX 77030
| | | | - Dan M. Roden
- Medicine and Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | | | - Robert T. Dirksen
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14627; and
| | - Mark E. Anderson
- Departments of Medicine and Physiology and Biophysics, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242
| | - Susan L. Hamilton
- Departments of Molecular Physiology and Biophysics
- To whom correspondence should be addressed at:
Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030. E-mail:
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Liu N, Colombi B, Memmi M, Zissimopoulos S, Rizzi N, Negri S, Imbriani M, Napolitano C, Lai FA, Priori SG. Arrhythmogenesis in catecholaminergic polymorphic ventricular tachycardia: insights from a RyR2 R4496C knock-in mouse model. Circ Res 2006; 99:292-8. [PMID: 16825580 DOI: 10.1161/01.res.0000235869.50747.e1] [Citation(s) in RCA: 229] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited disease characterized by life threatening arrhythmias and mutations in the gene encoding the ryanodine receptor (RyR2). Disagreement exists on whether (1) RyR2 mutations induce abnormal calcium transients in the absence of adrenergic stimulation; (2) decreased affinity of mutant RyR2 for FKBP12.6 causes CPVT; (3) K201 prevent arrhythmias by normalizing the FKBP12.6-RyR2 binding. We studied ventricular myocytes isolated from wild-type (WT) and knock-in mice harboring the R4496C mutation (RyR2(R4496C+/-)). Pacing protocols did not elicit delayed afterdepolarizations (DADs) (n=20) in WT but induced DADs in 21 of 33 (63%) RyR2(R4496C+/-) myocytes (P=0.001). Superfusion with isoproterenol (30 nmol/L) induced small DADs (45%) and no triggered activity in WT myocytes, whereas it elicited DADs in 87% and triggered activity in 60% of RyR2(R4496C+/-) myocytes (P=0.001). DADs and triggered activity were abolished by ryanodine (10 micromol/L) but not by K201 (1 micromol/L or 10 micromol/L). In vivo administration of K201 failed to prevent induction of polymorphic ventricular tachycardia (VT) in RyR2(R4496C+/-) mice. Measurement of the FKBP12.6/RyR2 ratio in the heavy sarcoplasmic reticulum membrane showed normal RyR2-FKBP12.6 interaction both in WT and RyR2(R4496C+/-) either before and after treatment with caffeine and epinephrine. We suggest that (1) triggered activity is the likely arrhythmogenic mechanism of CPVT; (2) K201 fails to prevent DADs in RyR2(R4496C+/-) myocytes and ventricular arrhythmias in RyR2(R4496C+/-) mice; and (3) RyR2-FKBP12.6 interaction in RyR2(R4496C+/-) is identical to that of WT both before and after epinephrine and caffeine, thus suggesting that it is unlikely that the R4496C mutation interferes with the RyR2/FKBP12.6 complex.
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Affiliation(s)
- Nian Liu
- Molecular Cardiology, IRCCS Fondazione Salvatore Maugeri, Pavia, Italy
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