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Yalçin SS, Dönmez Y, Aypar E, Yalçin S. Element profiles in blood and teeth samples of children with congenital heart diseases in comparison with healthy ones. J Trace Elem Med Biol 2021; 63:126662. [PMID: 33126039 DOI: 10.1016/j.jtemb.2020.126662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 07/29/2020] [Accepted: 09/28/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Some elements were claimed to play a role in the pathogenesis of congenital heart defects (CHD) and influence the general well-being and health of these children. OBJECTIVES We aimed to assess the levels of some elements simultaneously in the blood and teeth samples of children with cyanotic and acyanotic CHD compared with healthy children. METHODS A total of 39 children with CHD (11 with cyanotic and 28 with acyanotic CHD) and 42 age- and sex-adjusted controls were enrolled. Levels of 13 elements, including magnesium, phosphorus, calcium, chromium, manganese, iron, copper, zinc, strontium, cadmium, lead, mercury, and molybdenum, were assessed using inductively coupled plasma mass spectrometry. RESULTS Children with cyanotic and acyanotic CHD had significantly lower teeth calcium and calcium/phosphorus ratio as compared to the controls after adjusting for confounders. The mean blood iron level was found to be significantly higher in the cyanotic CHD group compared to the other groups. In addition, children with acyanotic CHD had significantly higher teeth copper levels, higher blood molybdenum and lower blood magnesium levels compared to the healthy control group. Blood cadmium and mercury levels were found to be significantly elevated in both the cyanotic and acyanotic CHD groups compared to the healthy control group. There were no differences in toxic metal levels of teeth in cases with CHD. CONCLUSION Monitoring adequate and balanced gestational micronutrient intake might support not only maternal health but also fetal cardiac development and infant well-being. Supplementation of magnesium should be evaluated in patients having CHD.
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Affiliation(s)
- Sıddıka Songül Yalçin
- Unit of Social Pediatrics, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
| | - Yasemin Dönmez
- Unit of Pediatric Cardiology, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Ebru Aypar
- Unit of Pediatric Cardiology, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Suzan Yalçin
- Department of Food Hygiene and Technology, Faculty of Veterinary Medicine, Selçuk University, Konya, Turkey
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2
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Chu L, Yin H, Gao L, Gao L, Xia Y, Zhang C, Chen Y, Liu T, Huang J, Boheler KR, Zhou Y, Yang HT. Cardiac Na +-Ca 2+ exchanger 1 (ncx1h) is critical for the ventricular cardiomyocyte formation via regulating the expression levels of gata4 and hand2 in zebrafish. Sci China Life Sci 2020; 64:255-268. [PMID: 32648190 DOI: 10.1007/s11427-019-1706-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 04/22/2020] [Indexed: 10/23/2022]
Abstract
Ca2+ signaling is critical for heart development; however, the precise roles and regulatory pathways of Ca2+ transport proteins in cardiogenesis remain largely unknown. Sodium-calcium exchanger 1 (Ncx1) is responsible for Ca2+ efflux in cardiomyocytes. It is involved in cardiogenesis, while the mechanism is unclear. Here, using the forward genetic screening in zebrafish, we identified a novel mutation at a highly-conserved leucine residue in ncx1 gene (mutantLDD353/ncx1hL154P) that led to smaller hearts with reduced heart rate and weak contraction. Mechanistically, the number of ventricular but not atrial cardiomyocytes was reduced in ncx1hL154P zebrafish. These defects were mimicked by knockdown or knockout of ncx1h. Moreover, ncx1hL154P had cytosolic and mitochondrial Ca2+ overloading and Ca2+ transient suppression in cardiomyocytes. Furthermore, ncx1hL154P and ncx1h morphants downregulated cardiac transcription factors hand2 and gata4 in the cardiac regions, while overexpression of hand2 and gata4 partially rescued cardiac defects including the number of ventricular myocytes. These findings demonstrate an essential role of the novel 154th leucine residue in the maintenance of Ncx1 function in zebrafish, and reveal previous unrecognized critical roles of the 154th leucine residue and Ncx1 in the formation of ventricular cardiomyocytes by at least partially regulating the expression levels of gata4 and hand2.
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Affiliation(s)
- Liming Chu
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Laboratory of Molecular Cardiology and Laboratory of Development and Diseases, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences (CAS), CAS, Shanghai, 200031, China.,Institute for Stem Cell and Regeneration, CAS, Beijing, 100101, China
| | - Huimin Yin
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Laboratory of Molecular Cardiology and Laboratory of Development and Diseases, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences (CAS), CAS, Shanghai, 200031, China.,Institute for Stem Cell and Regeneration, CAS, Beijing, 100101, China
| | - Lei Gao
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Laboratory of Molecular Cardiology and Laboratory of Development and Diseases, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences (CAS), CAS, Shanghai, 200031, China.,Institute for Stem Cell and Regeneration, CAS, Beijing, 100101, China
| | - Li Gao
- State Key Laboratory for Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Yu Xia
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Laboratory of Molecular Cardiology and Laboratory of Development and Diseases, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences (CAS), CAS, Shanghai, 200031, China.,Institute for Stem Cell and Regeneration, CAS, Beijing, 100101, China
| | - Chiyuan Zhang
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Laboratory of Molecular Cardiology and Laboratory of Development and Diseases, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences (CAS), CAS, Shanghai, 200031, China.,Institute for Stem Cell and Regeneration, CAS, Beijing, 100101, China
| | - Yi Chen
- State Key Laboratory for Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Tingxi Liu
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Laboratory of Molecular Cardiology and Laboratory of Development and Diseases, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences (CAS), CAS, Shanghai, 200031, China.,Institute for Stem Cell and Regeneration, CAS, Beijing, 100101, China
| | - Jijun Huang
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Laboratory of Molecular Cardiology and Laboratory of Development and Diseases, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences (CAS), CAS, Shanghai, 200031, China.,Institute for Stem Cell and Regeneration, CAS, Beijing, 100101, China
| | - Kenneth R Boheler
- Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Yong Zhou
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Laboratory of Molecular Cardiology and Laboratory of Development and Diseases, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences (CAS), CAS, Shanghai, 200031, China. .,Institute for Stem Cell and Regeneration, CAS, Beijing, 100101, China.
| | - Huang-Tian Yang
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Laboratory of Molecular Cardiology and Laboratory of Development and Diseases, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences (CAS), CAS, Shanghai, 200031, China. .,Institute for Stem Cell and Regeneration, CAS, Beijing, 100101, China.
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Stewart TA, Davis FM. An element for development: Calcium signaling in mammalian reproduction and development. Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 2019; 1866:1230-8. [DOI: 10.1016/j.bbamcr.2019.02.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 02/22/2019] [Accepted: 02/24/2019] [Indexed: 11/21/2022]
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Hwa JJ, Beckouche N, Huang L, Kram Y, Lindskog H, Wang RA. Abnormal arterial-venous fusions and fate specification in mouse embryos lacking blood flow. Sci Rep 2017; 7:11965. [PMID: 28931948 PMCID: PMC5607254 DOI: 10.1038/s41598-017-12353-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 08/25/2017] [Indexed: 02/08/2023] Open
Abstract
The functions of blood flow in the morphogenesis of mammalian arteries and veins are not well understood. We examined the development of the dorsal aorta (DA) and the cardinal vein (CV) in Ncx1 -/- mutants, which lack blood flow due to a deficiency in a sodium calcium ion exchanger expressed specifically in the heart. The mutant DA and CV were abnormally connected. The endothelium of the Ncx1 -/- mutant DA lacked normal expression of the arterial markers ephrin-B2 and Connexin-40. Notch1 activation, known to promote arterial specification, was decreased in mutant DA endothelial cells (ECs), which ectopically expressed the venous marker Coup-TFII. These findings suggest that flow has essential functions in the DA by promoting arterial and suppressing venous marker expression. In contrast, flow plays a lesser role in the CV, because expression of arterial-venous markers in CV ECs was not as dramatically affected in Ncx1 -/- mutants. We propose a molecular mechanism by which blood flow mediates DA and CV morphogenesis, by regulating arterial-venous specification of DA ECs to ensure proper separation of the developing DA and CV.
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Affiliation(s)
- Jennifer J Hwa
- Laboratory for Accelerated Vascular Research, Division of Vascular Surgery, Department of Surgery, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Nathan Beckouche
- Laboratory for Accelerated Vascular Research, Division of Vascular Surgery, Department of Surgery, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Lawrence Huang
- Laboratory for Accelerated Vascular Research, Division of Vascular Surgery, Department of Surgery, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Yoseph Kram
- Laboratory for Accelerated Vascular Research, Division of Vascular Surgery, Department of Surgery, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Henrik Lindskog
- Laboratory for Accelerated Vascular Research, Division of Vascular Surgery, Department of Surgery, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Rong A Wang
- Laboratory for Accelerated Vascular Research, Division of Vascular Surgery, Department of Surgery, University of California, San Francisco, San Francisco, CA, 94143, USA.
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Shimizu H, Langenbacher AD, Huang J, Wang K, Otto G, Geisler R, Wang Y, Chen JN. The Calcineurin-FoxO-MuRF1 signaling pathway regulates myofibril integrity in cardiomyocytes. eLife 2017; 6:27955. [PMID: 28826496 PMCID: PMC5576919 DOI: 10.7554/elife.27955] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 08/18/2017] [Indexed: 12/21/2022] Open
Abstract
Altered Ca2+ handling is often present in diseased hearts undergoing structural remodeling and functional deterioration. However, whether Ca2+ directly regulates sarcomere structure has remained elusive. Using a zebrafish ncx1 mutant, we explored the impacts of impaired Ca2+ homeostasis on myofibril integrity. We found that the E3 ubiquitin ligase murf1 is upregulated in ncx1-deficient hearts. Intriguingly, knocking down murf1 activity or inhibiting proteasome activity preserved myofibril integrity, revealing a MuRF1-mediated proteasome degradation mechanism that is activated in response to abnormal Ca2+ homeostasis. Furthermore, we detected an accumulation of the murf1 regulator FoxO in the nuclei of ncx1-deficient cardiomyocytes. Overexpression of FoxO in wild type cardiomyocytes induced murf1 expression and caused myofibril disarray, whereas inhibiting Calcineurin activity attenuated FoxO-mediated murf1 expression and protected sarcomeres from degradation in ncx1-deficient hearts. Together, our findings reveal a novel mechanism by which Ca2+ overload disrupts myofibril integrity by activating a Calcineurin-FoxO-MuRF1-proteosome signaling pathway.
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Affiliation(s)
- Hirohito Shimizu
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Adam D Langenbacher
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Jie Huang
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Kevin Wang
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Georg Otto
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Robert Geisler
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Yibin Wang
- Department of Anesthesiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,Department of Medicine and Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Jau-Nian Chen
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
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Kolanowski TJ, Antos CL, Guan K. Making human cardiomyocytes up to date: Derivation, maturation state and perspectives. Int J Cardiol 2017; 241:379-386. [DOI: 10.1016/j.ijcard.2017.03.099] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 02/24/2017] [Accepted: 03/21/2017] [Indexed: 12/29/2022]
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Simmons O, Bolanis EM, Wang J, Conway SJ. In situ hybridization (both radioactive and nonradioactive) and spatiotemporal gene expression analysis. Methods Mol Biol 2015; 1194:225-44. [PMID: 25064106 DOI: 10.1007/978-1-4939-1215-5_12] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Section in situ hybridization using either radioactive or nonradioactive labeled cDNA probes is an invaluable technique that enables the investigator to detect and localize mRNA expression within tissue sections and cells. Here, we describe the labeling of (35)S-UTP radioactive and nonradioactive digoxigenin probes, preparation of tissue sections, hybridization, and washing of non-hybridized probes, followed by the detection of radioactive signals via dipping in nuclear emulsion and the immunohistochemical and subsequent colorimetric detection of nonradioactive signals.
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Affiliation(s)
- Olga Simmons
- HB Wells Center for Pediatric Research, Indiana University School of Medicine, 1044 West Walnut Street, Room R4 W402E, Indianapolis, IN, 46202, USA
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Menick DR, Li MS, Chernysh O, Renaud L, Kimbrough D, Kasiganesan H, Mani SK. Transcriptional pathways and potential therapeutic targets in the regulation of Ncx1 expression in cardiac hypertrophy and failure. Adv Exp Med Biol 2013; 961:125-35. [PMID: 23224875 PMCID: PMC3624972 DOI: 10.1007/978-1-4614-4756-6_11] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Changes in cardiac gene expression contribute to the progression of heart failure by affecting cardiomyocyte growth, function, and survival. The Na(+)-Ca(2+) exchanger gene (Ncx1) is upregulated in hypertrophy and is often found elevated in end-stage heart failure. Studies have shown that the change in its expression contributes to contractile dysfunction. Several transcriptional pathways mediate Ncx1 expression in pathological cardiac remodeling. Both α-adrenergic receptor (α-AR) and β-adrenergic receptor (β-AR) signaling can play a role in the regulation of calcium homeostasis in the cardiomyocyte, but chronic activation in periods of cardiac stress contributes to heart failure by mechanisms which include Ncx1 upregulation. Our studies have even demonstrated that NCX1 can directly act as a regulator of "activity-dependent signal transduction" mediating changes in its own expression. Finally, we present evidence that histone deacetylases (HDACs) and histone acetyltransferases (HATs) act as master regulators of Ncx1 expression. We show that many of the transcription factors regulating Ncx1 expression are important in cardiac development and also in the regulation of many other genes in the so-called fetal gene program, which are activated by pathological stimuli. Importantly, studies have revealed that the transcriptional network regulating Ncx1 expression is also mediating many of the other changes in genetic remodeling contributing to the development of cardiac dysfunction and revealed potential therapeutic targets for the treatment of hypertrophy and failure.
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Nishii K, Morimoto S, Minakami R, Miyano Y, Hashizume K, Ohta M, Zhan DY, Lu QW, Shibata Y. Targeted disruption of the cardiac troponin T gene causes sarcomere disassembly and defects in heartbeat within the early mouse embryo. Dev Biol 2008; 322:65-73. [DOI: 10.1016/j.ydbio.2008.07.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 07/02/2008] [Accepted: 07/03/2008] [Indexed: 12/17/2022]
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10
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Haley SA, Zhao T, Zou L, Klysik JE, Padbury JF, Kochilas LK. Forced expression of the cell cycle inhibitor p57Kip2 in cardiomyocytes attenuates ischemia-reperfusion injury in the mouse heart. BMC Physiol 2008; 8:4. [PMID: 18312674 PMCID: PMC2268709 DOI: 10.1186/1472-6793-8-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Accepted: 02/29/2008] [Indexed: 01/04/2023]
Abstract
Background Myocardial hypoxic-ischemic injury is the cause of significant morbidity and mortality worldwide. The cardiomyocyte response to hypoxic-ischemic injury is known to include changes in cell cycle regulators. The cyclin-dependent kinase inhibitor p57Kip2 is involved in cell cycle control, differentiation, stress signaling and apoptosis. In contrast to other cyclin-dependent kinase inhibitors, p57Kip2 expression diminishes during postnatal life and is reactivated in the adult heart under conditions of cardiac stress. Overexpression of p57Kip2 has been previously shown to prevent apoptotic cell death in vitro by inhibiting stress-activated kinases. Therefore, we hypothesized that p57Kip2 has a protective role in cardiomyocytes under hypoxic conditions. To investigate this hypothesis, we created a transgenic mouse (R26loxpTA-p57k/+) that expresses p57Kip2 specifically in cardiac tissue under the ventricular cardiomyocyte promoter Mlc2v. Results Transgenic mice with cardiac specific overexpression of p57Kip2 are viable, fertile and normally active and their hearts are morphologically indistinguishable from the control hearts and have similar heart weight/body weight ratio. The baseline functional parameters, including left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP), LVdp/dtmax, heart rate (HR) and rate pressure product (RPR) were not significantly different between the different groups as assessed by the Langendorff perfused heart preparation. However, after subjecting the heart ex vivo to 30 minutes of ischemia-reperfusion injury, the p57Kip2 overexpressing hearts demonstrated preserved cardiac function compared to control mice with higher left ventricular developed pressure (63 ± 15 vs 30 ± 6 mmHg, p = 0.05), rate pressure product (22.8 ± 4.86 vs 10.4 ± 2.1 × 103bpm × mmHg, p < 0.05) and coronary flow (3.5 ± 0.5 vs 2.38 ± 0.24 ml/min, p <0.05). Conclusion These data suggest that forced cardiac expression of p57Kip2 does not affect myocardial growth, differentiation and baseline function but attenuates injury from ischemia-reperfusion in the adult mouse heart.
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Affiliation(s)
- Sheila A Haley
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA.
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Lux CT, Yoshimoto M, McGrath K, Conway SJ, Palis J, Yoder MC. All primitive and definitive hematopoietic progenitor cells emerging before E10 in the mouse embryo are products of the yolk sac. Blood 2008; 111:3435-8. [PMID: 17932251 DOI: 10.1182/blood-2007-08-107086] [Citation(s) in RCA: 212] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The relative contribution of yolk sac (YS)-derived cells to the circulating definitive hematopoietic progenitor cell (HPC) pool that seeds the fetal liver remains controversial due to the presence of systemic circulation and the onset of hematopoiesis within the embryo proper (EP) before liver seeding. Ncx1-/- embryos fail to initiate a heartbeat on embryonic day (E) 8.25, but continue to develop through E10. We detected normal numbers of primitive erythroid progenitors in Ncx1-/- versus wild type (WT) YS, but primitive erythroblasts did not circulate in the Ncx1-/- EP. While there was no significant difference in the number of definitive HPCs in Ncx1-/- versus WT YS through E9.5, the Ncx1-/- EP was nearly devoid of HPCs. Thus, primitive erythroblasts and essentially all definitive HPCs destined to initially seed the fetal liver after E9.5 are generated in the YS between E7.0-E9.5 and are redistributed into the EP via the systemic circulation.
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Menick DR, Renaud L, Buchholz A, Müller JG, Zhou H, Kappler CS, Kubalak SW, Conway SJ, Xu L. Regulation of Ncx1 gene expression in the normal and hypertrophic heart. Ann N Y Acad Sci 2007; 1099:195-203. [PMID: 17446459 PMCID: PMC3096001 DOI: 10.1196/annals.1387.058] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The Na+/Ca2+ exchanger (NCX1) is crucial in the regulation of [Ca2+]i in the cardiac myocyte. The exchanger is upregulated in cardiac hypertrophy, ischemia, and failure. This upregulation can have an effect on Ca2+ transients and possibly contribute to diastolic dysfunction and an increased risk of arrhythmias. Studies from both in vivo and in vitro model systems have provided an initial skeleton of the potential signaling pathways that regulate the exchanger during development, growth, and hypertrophy. The Ncx1 gene is upregulated in response to alpha-adrenergic stimulation. We have shown that this is via p38alpha activation of transcription factors binding to the Ncx1 promotor at the -80 CArG element. Interestingly, most of the elements, including the CArG element, which we have demonstrated to be important for regulation of Ncx1 expression are in the proximal 184 bp of the promotor. Using a transgenic mouse, we have shown that the proximal 184 bp is sufficient for expression of reporter genes in adult cardiomyocytes and for the correct spatiotemporal pattern of Ncx1 expression in development but not for upregulation in response to pressure overload.
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Affiliation(s)
- Donald R Menick
- Division of Cardiology, Department of Medicine, Gazes Cardiac Research Institute, Medical University of South Carolina, 114 Doughty St., Charleston, SC 29425, USA.
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Xu L, Renaud L, Müller JG, Baicu CF, Bonnema DD, Zhou H, Kappler CS, Kubalak SW, Zile MR, Conway SJ, Menick DR. Regulation of Ncx1 expression. Identification of regulatory elements mediating cardiac-specific expression and up-regulation. J Biol Chem 2006; 281:34430-40. [PMID: 16966329 PMCID: PMC3096005 DOI: 10.1074/jbc.m607446200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Na+-Ca2+ exchanger (NCX1) is up-regulated in hypertrophy and is often found up-regulated in end-stage heart failure. Studies have shown that the change in its expression contributes to contractile dysfunction. We have previously shown that the 1831-bp Ncx1 H1 (1831Ncx1) promoter directs cardiac-specific expression of the exchanger in both development and in the adult, and is sufficient for the up-regulation of Ncx1 in response to pressure overload. Here, we utilized adenoviral mediated gene transfer and transgenics to identify minimal regions and response elements that mediate Ncx1 expression in the heart. We demonstrate that the proximal 184 bp of the Ncx1 H1 (184Ncx1) promoter is sufficient for expression of reporter genes in adult cardiomyocytes and for the correct spatiotemporal pattern of Ncx1 expression in development but not for up-regulation in response to pressure overload. Mutational analysis revealed that both the -80 CArG and the -50 GATA elements were required for expression in isolated adult cardiomyocytes. Chromatin immunoprecipitation assays in adult cardiocytes demonstrate that SRF and GATA4 are associated with the proximal region of the endogenous Ncx1 promoter. Transgenic lines were established for the 1831Ncx1 promoter-luciferase containing mutations in the -80 CArG or -50 GATA element. No luciferase activity was detected during development, in the adult, or after pressure overload in any of the -80 CArG transgenic lines. The Ncx1 -50 GATA mutant promoter was sufficient for driving the normal spatiotemporal pattern of Ncx1 expression in development and for up-regulation in response to pressure overload but importantly, expression was no longer cardiac restricted. This work is the first in vivo study that demonstrates which cis elements are important for Ncx1 regulation.
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MESH Headings
- Adenoviridae/genetics
- Animals
- Base Sequence
- Cats
- Chromatin Immunoprecipitation
- Disease Models, Animal
- Embryo, Mammalian/cytology
- Embryo, Mammalian/metabolism
- Female
- Gene Expression Regulation, Developmental
- Genes, Reporter
- Heart/physiology
- Male
- Mice
- Mice, Transgenic
- Molecular Sequence Data
- Mutation/genetics
- Myocardium/metabolism
- Myocardium/pathology
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Promoter Regions, Genetic/physiology
- RNA, Messenger/metabolism
- Rats
- Regulatory Sequences, Nucleic Acid/physiology
- Sequence Homology, Nucleic Acid
- Sodium-Calcium Exchanger/genetics
- Sodium-Calcium Exchanger/metabolism
- Transgenes
- Up-Regulation
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Affiliation(s)
- Lin Xu
- Gazes Cardiac Research Institute, Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Ludivine Renaud
- Gazes Cardiac Research Institute, Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Joachim G. Müller
- Gazes Cardiac Research Institute, Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Catalin F. Baicu
- Gazes Cardiac Research Institute, Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - D. Dirk Bonnema
- Gazes Cardiac Research Institute, Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Hongming Zhou
- Cardiovascular Development Group, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Christiana S. Kappler
- Gazes Cardiac Research Institute, Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Steven W. Kubalak
- Gazes Cardiac Research Institute, Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Michael R. Zile
- Gazes Cardiac Research Institute, Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Simon J. Conway
- Cardiovascular Development Group, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Donald R. Menick
- Gazes Cardiac Research Institute, Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
- To whom correspondence should be addressed: 114 Doughty St. Charleston, SC 29425. Tel.: 843-876-5045;
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Langenbacher AD, Dong Y, Shu X, Choi J, Nicoll DA, Goldhaber JI, Philipson KD, Chen JN. Mutation in sodium-calcium exchanger 1 (NCX1) causes cardiac fibrillation in zebrafish. Proc Natl Acad Sci U S A 2005; 102:17699-704. [PMID: 16314583 PMCID: PMC1308881 DOI: 10.1073/pnas.0502679102] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cardiac fibrillation, a form of cardiac arrhythmia, is the most common cause of embolic stroke and death associated with heart failure. The molecular mechanisms underlying cardiac fibrillation are largely unknown. Here we report a zebrafish model for cardiac fibrillation. The hearts of zebrafish tremblor (tre) mutants exhibit chaotic movements and fail to develop synchronized contractions. Calcium imaging showed that normal calcium transients are absent in tre cardiomyocytes, and molecular cloning of the tre mutation revealed that the tre locus encodes the zebrafish cardiac-specific sodium-calcium exchanger (NCX) 1, NCX1h. Forced expression of NCX1h or other calcium-handling molecules restored synchronized heartbeats in tre mutant embryos in a dosage-dependent manner, demonstrating the critical role of calcium homeostasis in maintaining embryonic cardiac function. By creating mosaic zebrafish embryos, we showed that sporadic NCX1h-null cells were not sufficient to disrupt normal cardiac function, but clustered wild-type cardiomyocytes contract in unison in tre mutant hearts. These data signify the essential role of calcium homeostasis and NCX1h in establishing rhythmic contraction in the embryonic zebrafish heart.
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Affiliation(s)
- Adam D Langenbacher
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA 90095, USA
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15
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Otsu K, Kuruma A, Yanagida E, Shoji S, Inoue T, Hirayama Y, Uematsu H, Hara Y, Kawano S. Na+/K+ ATPase and its functional coupling with Na+/Ca2+ exchanger in mouse embryonic stem cells during differentiation into cardiomyocytes. Cell Calcium 2005; 37:137-51. [PMID: 15589994 DOI: 10.1016/j.ceca.2004.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2004] [Revised: 05/25/2004] [Accepted: 08/06/2004] [Indexed: 12/15/2022]
Abstract
Cardiomyocytes derived from mouse embryonic stem (mES) cells have been demonstrated to exhibit a time-dependent expression of ion channels and signal transduction pathways in electrophysiological studies. However, ion transporters, such as Na+/K+ ATPase (Na+ pump) or Na+/Ca2+ exchanger, which play crucial roles for cardiac function, have not been well studied in this system. In this study, we investigated the functional expression of Na+/K+ ATPase and Na+/Ca2+ exchanger in mES cells during in vitro differentiation into cardiomyocytes, as well as the functional coupling between the two transporters. By measuring [Na+]i and Na+ pump current (Ip), it was shown that an ouabain-high sensitive Na+/K+ ATPase was expressed functionally in undifferentiated mES cells and these activities increased during a time course of differentiation. Using RT-PCR, the expression of mRNA for alpha1-subunit and alpha3-subunit of the Na+/K+ ATPase could be detected in both undifferentiated mES cells and derived cardiomyocytes. In contrast alpha2-subunit mRNA could be detected only in derived cardiomyocytes but not in undifferentiated mES cells. mRNA for the Na+/Ca2+ exchanger 1 isoform (NCX1) could be detected in undifferentiated mES cells and its expression levels seemed to gradually increase throughout the differentiation accompanied by increasing its Ca2+ extrusion function. At the middle stages of differentiation (after 10-day induction), more than 75% derived cardiomyocytes exhibited [Ca2+]i oscillations by blocking of Na+/K+ ATPase, suggesting the functional coupling with Na+/Ca2+ exchanger. From these results and RT-PCR analysis, we conclude that alpha2-subunit Na+/K+ ATPase mainly contributes to establish the functional coupling with NCX1 at the middle stages of differentiation of cardiomyocytes.
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Affiliation(s)
- Keishi Otsu
- Department of Cardiovascular Diseases, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
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16
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Abstract
Since the advent of mouse targeted mutations, gene traps, an escalating use of a variety of complex transgenic manipulations, and large-scale chemical mutagenesis projects yielding many mutants with cardiovascular defects, it has become increasingly evident that defects within the heart and vascular system are largely responsible for the observed in utero lethality of the embryo and early fetus. If a transgenically altered embryo survives implantation but fails to be born, it usually indicates that there is some form of lethal cardiovascular defect present. A number of embryonic organ and body systems, including the central nervous system, gut, lungs, urogenital system, and musculoskeletal system appear to have little or no survival value in utero (Copp, 1995). Cardiovascular abnormalities include the failure to establish an adequate yolk-sac vascular circulation, which results in early lethality (E8.5-10.5); poor cardiac function (E9.0-birth); failure to undergo correct looping and chamber formation of the primitive heart tube (E9.0-11.0); improper septation, including division of the common ventricle and atria and the establishment of a divided outflow tract (E11.0-13.0); inadequate establishment of the cardiac conduction system (E12.0-birth); and the failure of the in utero cardiovascular system to adapt to adult life (birth) and close the interatrial and aorta-pulmonary trunk shunts that are required for normal fetal life. Importantly, the developmental timing of lethality is usually a good indicator of both the type of the cardiovascular defect present and may also suggest the possible underlying cause/s. The purpose of this review is both to review the literature and to provide a beginner's guide for analysing cardiovascular defects in mouse mutants.
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Affiliation(s)
- Simon J Conway
- Institute of Molecular Medicine and Genetics and Department of Cell Biology and Anatomy, Medical College of Georgia, Georgia.
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17
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Conway SJ, Kruzynska-Frejtag A, Wang J, Rogers R, Kneer PL, Chen H, Creazzo T, Menick DR, Koushik SV. Role of sodium-calcium exchanger (Ncx1) in embryonic heart development: a transgenic rescue? Ann N Y Acad Sci 2002; 976:268-81. [PMID: 12502569 DOI: 10.1111/j.1749-6632.2002.tb04749.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Na(+)/Ca(2+) exchanger (Ncx-1) is highly expressed in cardiomyocytes, is thought to be required to maintain a low intracellular Ca(2+) concentration, and may play a role in excitation-contraction coupling. Significantly, targeted deletion of Ncx-1 results in Ncx1-null embryos that do not have a spontaneously beating heart and die in utero. Ultrastructural analysis revealed gross anomalies in the Ncx1-null contractile apparatus, but physiologic analysis showed normal field-stimulated Ca(2+) transients, suggesting that Ncx-1 function may not be critical for Ca(2+) extrusion from the cytosol as previously thought. Using caffeine to empty the intracellular Ca(2+) stores, we show that the sarcoplasmic reticulum is not fully functional within the 9.5-dpc mouse heart, indicating that the sarcoplasmic reticulum is unlikely to account for the unexpected maintenance of intracellular Ca(2+) homeostasis. Using the Ncx1-lacZ reporter, our data indicate restricted expression patterns of Ncx1 and that Ncx1 is highly expressed within the conduction system, suggesting Ncx1 may be required for spontaneous pacemaking activity. To test this hypothesis, we used transgenic mice overexpressing one of the two known adult Ncx1 isoforms under the control of the cardiac-specific a-myosin heavy chain promoter to restore Ncx1 expression within the Ncx1-null hearts. Results indicate that the transgenic re-expression of one Ncx1 isoform was unable to rescue the lethal null mutant phenotype. Furthermore, our in situ results indicate that both known adult Ncx1 isoforms are coexpressed within the embryonic heart, suggesting that effective transgenic rescue may require the presence of both isoforms within the developing heart.
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Affiliation(s)
- Simon J Conway
- Institute of Molecular Medicine and Genetics and Department of Cell Biology and Anatomy, Medical College of Georgia, Augusta, Georgia 30912, USA.
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18
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Yang HT, Tweedie D, Wang S, Guia A, Vinogradova T, Bogdanov K, Allen PD, Stern MD, Lakatta EG, Boheler KR. The ryanodine receptor modulates the spontaneous beating rate of cardiomyocytes during development. Proc Natl Acad Sci U S A 2002; 99:9225-30. [PMID: 12089338 PMCID: PMC123122 DOI: 10.1073/pnas.142651999] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In adult myocardium, the heartbeat originates from the sequential activation of ionic currents in pacemaker cells of the sinoatrial node. Ca(2+) release via the ryanodine receptor (RyR) modulates the rate at which these cells beat. In contrast, the mechanisms that regulate heart rate during early cardiac development are poorly understood. Embryonic stem (ES) cells can differentiate into spontaneously contracting myocytes whose beating rate increases with differentiation time. These cells thus offer an opportunity to determine the mechanisms that regulate heart rate during development. Here we show that the increase in heart rate with differentiation is markedly depressed in ES cell-derived cardiomyocytes with a functional knockout (KO) of the cardiac ryanodine receptor (RyR2). KO myocytes show a slowing of the rate of spontaneous diastolic depolarization and an absence of calcium sparks. The depressed rate of pacemaker potential can be mimicked in wild-type myocytes by ryanodine, and rescued in KO myocytes with herpes simplex virus (HSV)-1 amplicons containing full-length RyR2. We conclude that a functional RyR2 is crucial to the progressive increase in heart rate during differentiation of ES cell-derived cardiomyocytes, consistent with a mechanism that couples Ca(2+) release via RyR before an action potential with activation of an inward current that accelerates membrane depolarization.
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Affiliation(s)
- Huang-Tian Yang
- National Institute on Aging, Laboratory of Cardiovascular Science, National Institutes of Health, Baltimore, MD 21224, USA
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19
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Müller JG, Isomatsu Y, Koushik SV, O'Quinn M, Xu L, Kappler CS, Hapke E, Zile MR, Conway SJ, Menick DR. Cardiac-specific expression and hypertrophic upregulation of the feline Na(+)-Ca(2+) exchanger gene H1-promoter in a transgenic mouse model. Circ Res 2002; 90:158-64. [PMID: 11834708 DOI: 10.1161/hh0202.103231] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The NCX1 gene contains three promoters (H1, K1, and Br1), and as a result of alternative promoter usage and alternative splicing, there are multiple tissue-specific variants of the Na(+)-Ca(2+) exchanger. We have proposed that for NCX1, the H1 promoter regulates expression in the heart, the K1 promoter regulates expression in the kidney, and the Br1 promoter regulates expression in the brain as well as low-level ubiquitous expression. Here, using a transgenic mouse model, we test the role of the DNA region including -1831 to 67 bp of intron 1, encompassing exon H1 of the feline NCX1 gene (NCX1H1). The NCX1H1 promoter was sufficient for driving the normal spatiotemporal pattern of NCX1 expression in cardiac development. The luciferase reporter gene was expressed in a heart-restricted pattern both in early embryos (embryonic days 8 to 14) and in later embryos (after embryonic day 14), when NCX1 is also expressed in other tissues. In the adult, no luciferase activity was detected in the kidney, liver, spleen, uterus, or skeletal muscle; minimal activity was detected in the brain; and very high levels of luciferase expression were detected in the heart. Transverse aortic constriction-operated mice showed significantly increased left ventricular mass after 7 days. In addition, there was a 2-fold upregulation of NCX1H1 promoter activity in the left ventricle in animals after 7 days of pressure overload compared with both control and sham-operated animals. This work demonstrates that the NCX1H1 promoter directs cardiac-specific expression of the exchanger in both the embryo and adult and is also sufficient for the upregulation of NCX1 in response to pressure overload.
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Affiliation(s)
- Joachim G Müller
- Gazes Cardiac Research Institute and Division of Cardiology, Medical University of South Carolina, Ralph H. Johnson Department of Veterans Affairs, Charleston, SC 29425, USA
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20
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Koban MU, Brugh SA, Riordon DR, Dellow KA, Yang HT, Tweedie D, Boheler KR. A distant upstream region of the rat multipartite Na(+)-Ca(2+) exchanger NCX1 gene promoter is sufficient to confer cardiac-specific expression. Mech Dev 2001; 109:267-79. [PMID: 11731239 DOI: 10.1016/s0925-4773(01)00548-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Na(+)-Ca(2+) exchanger (NCX) regulates intracellular calcium homeostasis. We report on an upstream region of the rat NCX1 multipartite promoter that is active in cardiac myocytes. Although inactive in most non-cardiac cell lines, its activity can be rescued by cotransfection with GATA-4 and -6, but not GATA-5 transcription factors. In transgenic mice and similar to endogenous NCX1 mRNA expression, the upstream promoter region directs uniform beta-galactosidase expression in cardiac myocytes from approximately 7.75dpc. In adult mouse hearts, promoter activity is, however, significantly reduced and heterogeneous, except in the conduction system (sinoatrial and atrioventricular node, atrioventricular bundles). The upstream NCX1 promoter region thus directs appropriate spatial and temporal control of cardiac expression throughout development.
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Affiliation(s)
- M U Koban
- Department of Cardiothoracic Surgery, The National Heart and Lung Institute, Imperial College School of Medicine, London, UK
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21
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Wakimoto K, Kuro-o M, Yanaka N, Komuro I, Nabeshima YI, Imai Y. Expression of Na+/Ca(2+) exchanger (NCX1) gene in the developmental mouse embryo and adult mouse brain. Comp Biochem Physiol B Biochem Mol Biol 2001; 130:191-8. [PMID: 11544089 DOI: 10.1016/s1096-4959(01)00425-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Na(+)/Ca(2+) exchanger gene, NCX1, is widely expressed in many tissues, encoding several isoforms through alternative RNA splicing. NCX1 deficient mice are known to be lethal at embryonic day 9-10 (E9-10). However, its expression pattern during embryogenesis is largely unknown. Therefore, to identify and compare the localization and alternatively spliced isoforms of NCX1 mRNA expressed in the developmental stages, we analyzed the mouse embryo. Northern blot analysis demonstrated that NCX1 mRNA was expressed from the earliest stage examined, E7. In situ hybridization analysis revealed that NCX1 mRNA was expressed in the heart alone until E10.5. However, at E14.5 and 16.5, NCX1 mRNA was expressed not only in the heart, but also in neuronal cells. In addition, the expression of NCX1 mRNA in the adult brain was most abundant in the hippocampus. Using reverse transcription-polymerase chain reaction (RT-PCR), we also identified the alternatively spliced isoforms expressed during each developmental stage. The restricted expression of the NCX1 gene suggested that NCX1 may play an important role in the developing mouse embryo.
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Affiliation(s)
- K Wakimoto
- Discovery Research Laboratory, Tanabe Seiyaku Co., Ltd, 3-16-89 Kashima, Yodogawa-ku, Osaka 532-8505, Japan.
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22
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Linask KK, Han MD, Artman M, Ludwig CA. Sodium-calcium exchanger (NCX-1) and calcium modulation: NCX protein expression patterns and regulation of early heart development. Dev Dyn 2001; 221:249-64. [PMID: 11458386 DOI: 10.1002/dvdy.1131] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ouabain-induced inhibition of early heart development indicated that Na/K-ATPase plays an important role in maintaining normal ionic balances during differentiation of cardiomyocytes (Linask and Gui [1995] Dev Dyn 203:93-105). Inhibition of the sodium pump is generally accepted to affect the activity of the Na(+)-Ca(++) exchanger (NCX) to increase intracellular [Ca(++)]. These previous findings suggested that Ca(++) signaling may be an important modulator during differentiation of cardiomyocytes. In order to identify a connection between heart development and NCX-mediated Ca(++) regulation, we determined the embryonic spatiotemporal protein expression pattern of NCX-1 during early developmental stages. In both chick and mouse embryos, NCX-1 (the cardiac NCX isoform) is asymmetrically expressed during gastrulation; in the right side of the Hensen's node in the chick, in the right lateral mesoderm in the mouse. At slightly later stages, NCX-1 is expressed in the heart fields at comparable stages of heart development, in the chick at stage 7 and in the mouse at embryonic day (ED) 7.5. By ED 8 in the mouse, the exchanger protein displays a rostrocaudal difference in cardiac expression and an outer curvature-inner curvature ventricular difference. By ED 9.5, cardiac expression has increased from that seen at ED8 and NCX-1 is distributed throughout the myocardium consistent with the possibility that it is important in regulating initial cardiac contractile function. Only a low level of expression is detected in inflow and outflow regions. To substantiate a role for the involvement of calcium-mediated signaling, using pharmacologic approaches, ionomycin (a Ca(++) ionophore) was shown to perturb cardiac cell differentiation in a manner similar to ouabain as assayed by cNkx2.5 and sarcomeric myosin heavy chain expression. In addition, we show that an inhibitor of NCX, KB-R7943, can similarly and adversely affect early cardiac development at stage 4/5 and arrests cardiac cell contractility in 12-somite embryos. Thus, based upon NCX-1 protein expression patterns in the embryo, experimental Ca(++) modulation, and inhibition of NCX activity by KB-R7943, these results suggest an early and central role for calcium-mediated signaling in cardiac cell differentiation and NCX's regulation of the initial heartbeats in the embryo.
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Affiliation(s)
- K K Linask
- Department of Cell Biology, University of Medicine and Dentistry of New Jersey (UMDNJ), School of Osteopathic Medicine, Stratford, New Jersey 08084, USA.
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23
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Abstract
Abstract
—The Na
+
-Ca
2+
exchanger (NCX) is one of the essential regulators of Ca
2+
homeostasis in cardiomyocytes and thus an important modulator of the cardiac contractile function. The purpose of this review is to survey recent advances in cardiac NCX research, with particular emphasis on molecular and pharmacological aspects. The NCX function is thought to be regulated by a variety of cellular factors. However, data obtained by use of different experimental systems often appear to be in conflict. Where possible, we endeavor to provide a rational interpretation of such data. We also provide a summary of current work relating to the structure and function of the cardiac NCX. Recent molecular studies of the NCX protein are beginning to shed light on structural features of the ion translocation pathway in the NCX membrane domain, which seems likely to be formed, at least partly, by the phylogenetically conserved α-1 and α-2 repeat structures and their neighboring membrane-spanning segments. Finally, we discuss new classes of NCX inhibitors with improved selectivity. One of these, 2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea methanesulfonate (KB-R7943), appears to exhibit unique selectivity for Ca
2+
-influx–mode NCX activity. Data obtained with these inhibitors should provide a basis for designing more selective and clinically useful drugs targeting NCX.
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Affiliation(s)
- M Shigekawa
- Department of Molecular Physiology, National Cardiovascular Center Research Institute, Suita, Osaka, Japan.
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24
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Koushik SV, Wang J, Rogers R, Moskophidis D, Lambert NA, Creazzo TL, Conway SJ. Targeted inactivation of the sodium-calcium exchanger (Ncx1) results in the lack of a heartbeat and abnormal myofibrillar organization. FASEB J 2001; 15:1209-11. [PMID: 11344090 DOI: 10.1096/fj.00-0696fje] [Citation(s) in RCA: 200] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- S V Koushik
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912-2640, USA
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25
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Kruzynska-Frejtag A, Machnicki M, Rogers R, Markwald RR, Conway SJ. Periostin (an osteoblast-specific factor) is expressed within the embryonic mouse heart during valve formation. Mech Dev 2001; 103:183-8. [PMID: 11335131 DOI: 10.1016/s0925-4773(01)00356-2] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Periostin was originally isolated as a osteoblast-specific factor that functions as a cell adhesion molecule for preosteoblasts and is thought to be involved in osteoblast recruitment, attachment and spreading. Additionally, periostin expression has previously been shown to be significantly increased by both transforming growth factor beta-1(TGFbeta1) and bone morphogenetic protein (BMP)-2. Likewise the endocardial cushions that form within embryonic heart tube (embryonic day (E)10-13) are formed by the recruitment, attachment and spreading of endocardial cells into the overlying extracellular matrix, in response to secreted growth factors of the TGFbeta and BMP families. In order to determine whether periostin is similarly involved in heart morphogenesis, in situ hybridization and reverse transcription-polymerase chain reaction were used to detect periostin mRNA expression in the developing mouse heart. We show for the first time that periostin mRNA is expressed in the developing mouse embryonic and fetal heart, and that it is localized to the endocardial cushions that ultimately divide the primitive heart tube into a four-chambered heart.
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Affiliation(s)
- A Kruzynska-Frejtag
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, 1120 15th Street, Augusta, GA 30912, USA
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