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Barry C, Rouhana S, Braun JL, Geromella MS, Fajardo VA, Pyle WG. Perimenopause Decreases SERCA2a Activity in the Hearts of a Mouse Model of Ovarian Failure. Biomolecules 2024; 14:675. [PMID: 38927078 PMCID: PMC11201532 DOI: 10.3390/biom14060675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2024] [Revised: 06/06/2024] [Accepted: 06/07/2024] [Indexed: 06/28/2024] Open
Abstract
Risk of cardiovascular disease mortality rises in women after menopause. While increased cardiovascular risk is largely attributed to postmenopausal declines in estrogens, the molecular changes in the heart that contribute to risk are poorly understood. Disruptions in intracellular calcium handling develop in ovariectomized mice and have been implicated in cardiac dysfunction. Using a mouse model of menopause in which ovarian failure occurs over 120 days, we sought to determine if perimenopause impacted calcium removal mechanisms in the heart and identify the molecular mechanisms. Mice were injected with 4-vinylcyclohexene diepoxide (VCD) to induce ovarian failure over 120 days, mimicking perimenopause. Hearts were removed at 60 and 120 days after VCD injections, representing the middle and end of perimenopause. SERCA2a function was significantly diminished at the end of perimenopause. Neither SERCA2a nor phospholamban expression changed at either time point, but phospholamban phosphorylation at S16 and T17 was dynamically altered. Intrinsic SERCA inhibitors sarcolipin and myoregulin increased >4-fold at day 60, as did the native activator DWORF. At the end of perimenopause, sarcolipin and myoregulin returned to baseline levels while DWORF was significantly reduced below controls. Sodium-calcium exchanger expression was significantly increased at the end of perimenopause. These results show that the foundation for increased cardiovascular disease mortality develops in the heart during perimenopause and that regulators of calcium handling exhibit significant fluctuations over time. Understanding the temporal development of cardiovascular risk associated with menopause and the underlying mechanisms is critical to developing interventions that mitigate the rise in cardiovascular mortality that arises after menopause.
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Affiliation(s)
- Ciara Barry
- IMPART Team Canada Investigator Network, Dalhousie Medicine, Saint John, NB E2K 5E2, Canada
| | - Sarah Rouhana
- IMPART Team Canada Investigator Network, Dalhousie Medicine, Saint John, NB E2K 5E2, Canada
| | - Jessica L. Braun
- Centre for Bone and Muscle Health, Brock University, St. Catharines, ON L2S 3A1, Canada (V.A.F.)
- Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Mia S. Geromella
- Centre for Bone and Muscle Health, Brock University, St. Catharines, ON L2S 3A1, Canada (V.A.F.)
- Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Val A. Fajardo
- Centre for Bone and Muscle Health, Brock University, St. Catharines, ON L2S 3A1, Canada (V.A.F.)
- Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - W. Glen Pyle
- IMPART Team Canada Investigator Network, Dalhousie Medicine, Saint John, NB E2K 5E2, Canada
- Women’s Health Research Institute at BC Women’s Hospital + Health Centre, Vancouver, BC V6H 2N9, Canada
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Hilderink S, Schuldt M, Goebel M, Jansen VJ, Manders E, Moorman S, Dorsch LM, van Steenbeek FG, van der Velden J, Kuster DWD. Characterization of heterozygous and homozygous mouse models with the most common hypertrophic cardiomyopathy mutation MYBPC3 c.2373InsG in the Netherlands. J Mol Cell Cardiol 2023; 185:65-76. [PMID: 37844837 DOI: 10.1016/j.yjmcc.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 09/25/2023] [Accepted: 10/11/2023] [Indexed: 10/18/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is frequently caused by mutations in the cardiac myosin binding protein-C (cMyBP-C) encoding gene MYBPC3. In the Netherlands, approximately 25% of patients carry the MYBPC3c.2373InsG founder mutation. Most patients are heterozygous (MYBPC3+/InsG) and have highly variable phenotypic expression, whereas homozygous (MYBPC3InsG/InsG) patients have severe HCM at a young age. To improve understanding of disease progression and genotype-phenotype relationship based on the hallmarks of human HCM, we characterized mice with CRISPR/Cas9-induced heterozygous and homozygous mutations. At 18-28 weeks of age, we assessed the cardiac phenotype of Mybpc3+/InsG and Mybpc3InsG/InsG mice with echocardiography, and performed histological analyses. Cytoskeletal proteins and cardiomyocyte contractility of 3-4 week old and 18-28 week old Mybpc3c.2373InsG mice were compared to wild-type (WT) mice. Expectedly, knock-in of Mybpc3c.2373InsG resulted in the absence of cMyBP-C and our 18-28 week old homozygous Mybpc3c.2373InsG model developed cardiac hypertrophy and severe left ventricular systolic and diastolic dysfunction, whereas HCM was not evident in Mybpc3+/InsG mice. Mybpc3InsG/InsG cardiomyocytes also presented with slowed contraction-relaxation kinetics, to a greater extent in 18-28 week old mice, partially due to increased levels of detyrosinated tubulin and desmin, and reduced cardiac troponin I (cTnI) phosphorylation. Impaired cardiomyocyte contraction-relaxation kinetics were successfully normalized in 18-28 week old Mybpc3InsG/InsG cardiomyocytes by combining detyrosination inhibitor parthenolide and β-adrenergic receptor agonist isoproterenol. Both the 3-4 week old and 18-28 week old Mybpc3InsG/InsG models recapitulate HCM, with a severe phenotype present in the 18-28 week old model.
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Affiliation(s)
- Sarah Hilderink
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Maike Schuldt
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Max Goebel
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Valentijn J Jansen
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Emmy Manders
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands
| | - Stan Moorman
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Larissa M Dorsch
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Frank G van Steenbeek
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands; Department of Cardiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht University, 3508 GA Utrecht, the Netherlands; Regenerative Medicine Center Utrecht, University Medical Center Utrecht, Utrecht University, 3584 CT Utrecht, the Netherlands
| | - Jolanda van der Velden
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Diederik W D Kuster
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands.
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Espinoza-Derout J, Arambulo JML, Ramirez-Trillo W, Rivera JC, Hasan KM, Lao CJ, Jordan MC, Shao XM, Roos KP, Sinha-Hikim AP, Friedman TC. The lipolysis inhibitor acipimox reverses the cardiac phenotype induced by electronic cigarettes. Sci Rep 2023; 13:18239. [PMID: 37880325 PMCID: PMC10600141 DOI: 10.1038/s41598-023-44082-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 10/03/2023] [Indexed: 10/27/2023] Open
Abstract
Electronic cigarettes (e-cigarettes) are a prevalent alternative to conventional nicotine cigarettes among smokers and people who have never smoked. Increased concentrations of serum free fatty acids (FFAs) are crucial in generating lipotoxicity. We studied the effects of acipimox, an antilipolytic drug, on e-cigarette-induced cardiac dysfunction. C57BL/6J wild-type mice on high fat diet were treated with saline, e-cigarette with 2.4% nicotine [e-cigarette (2.4%)], and e-cigarette (2.4%) plus acipimox for 12 weeks. Fractional shortening and ejection fraction were diminished in mice exposed to e-cigarettes (2.4%) compared with saline and acipimox-treated mice. Mice exposed to e-cigarette (2.4%) had increased circulating levels of inflammatory cytokines and FFAs, which were diminished by acipimox. Gene Set Enrichment Analysis revealed that e-cigarette (2.4%)-treated mice had gene expression changes in the G2/M DNA damage checkpoint pathway that was normalized by acipimox. Accordingly, we showed that acipimox suppressed the nuclear localization of phospho-p53 induced by e-cigarette (2.4%). Additionally, e-cigarette (2.4%) increased the apurinic/apyrimidinic sites, a marker of oxidative DNA damage which was normalized by acipimox. Mice exposed to e-cigarette (2.4%) had increased cardiac Heme oxygenase 1 protein levels and 4-hydroxynonenal (4-HNE). These markers of oxidative stress were decreased by acipimox. Therefore, inhibiting lipolysis with acipimox normalizes the physiological changes induced by e-cigarettes and the associated increase in inflammatory cytokines, oxidative stress, and DNA damage.
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Affiliation(s)
- Jorge Espinoza-Derout
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, 1731 E. 120th Street, Los Angeles, CA, 90059, USA.
- Departments of Physiology, Medicine, and Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, 90095, USA.
| | - Jose Mari Luis Arambulo
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, 1731 E. 120th Street, Los Angeles, CA, 90059, USA
| | - William Ramirez-Trillo
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, 1731 E. 120th Street, Los Angeles, CA, 90059, USA
| | - Juan Carlos Rivera
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, 1731 E. 120th Street, Los Angeles, CA, 90059, USA
| | - Kamrul M Hasan
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, 1731 E. 120th Street, Los Angeles, CA, 90059, USA
- Departments of Physiology, Medicine, and Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Candice J Lao
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, 1731 E. 120th Street, Los Angeles, CA, 90059, USA
- Departments of Physiology, Medicine, and Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Maria C Jordan
- Departments of Physiology, Medicine, and Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Xuesi M Shao
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, 1731 E. 120th Street, Los Angeles, CA, 90059, USA
- Departments of Physiology, Medicine, and Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Kenneth P Roos
- Departments of Physiology, Medicine, and Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Amiya P Sinha-Hikim
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, 1731 E. 120th Street, Los Angeles, CA, 90059, USA
- Departments of Physiology, Medicine, and Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Theodore C Friedman
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, 1731 E. 120th Street, Los Angeles, CA, 90059, USA
- Departments of Physiology, Medicine, and Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, 90095, USA
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Kitase Y, Vallejo JA, Dallas SL, Xie Y, Dallas M, Tiede-Lewis L, Moore D, Meljanac A, Kumar C, Zhao C, Rosser J, Brotto M, Johnson ML, Liu Z, Wacker MJ, Bonewald L. Body weight influences musculoskeletal adaptation to long-term voluntary wheel running during aging in female mice. Aging (Albany NY) 2022; 15:308-352. [PMID: 36403149 PMCID: PMC9925690 DOI: 10.18632/aging.204390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 11/02/2022] [Indexed: 11/19/2022]
Abstract
Frailty is the hallmark of aging that can be delayed with exercise. The present studies were initiated based on the hypothesis that long-term voluntary wheel running (VWR) in female mice from 12 to 18 or 22 months of age would have beneficial effects on the musculoskeletal system. Mice were separated into high (HBW) and low (LBW) body weight based on final body weights upon termination of experiments. Bone marrow fat was significantly higher in HBW than LBW under sedentary conditions, but not with VWR. HBW was more protective for soleus size and function than LBW under sedentary conditions, however VWR increased soleus size and function regardless of body weight. VWR plus HBW was more protective against muscle loss with aging. Similar effects of VWR plus HBW were observed with the extensor digitorum longus, EDL, however, LBW with VWR was beneficial in improving EDL fatigue resistance in 18 mo mice and was more beneficial with regards to muscle production of bone protective factors. VWR plus HBW maintained bone in aged animals. In summary, HBW had a more beneficial effect on muscle and bone with aging especially in combination with exercise. These effects were independent of bone marrow fat, suggesting that intrinsic musculoskeletal adaptions were responsible for these beneficial effects.
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Affiliation(s)
- Yukiko Kitase
- Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - Julian A. Vallejo
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, MO 64108, USA
- Department of Biomedical Sciences, School of Medicine, University of Missouri, Kansas City, MO 64108, USA
| | - Sarah L. Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, MO 64108, USA
| | - Yixia Xie
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, MO 64108, USA
| | - Mark Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, MO 64108, USA
| | - LeAnn Tiede-Lewis
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, MO 64108, USA
| | - David Moore
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, MO 64108, USA
| | - Anthony Meljanac
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, MO 64108, USA
| | - Corrine Kumar
- Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - Carrie Zhao
- Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - Jennifer Rosser
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, MO 64108, USA
| | - Marco Brotto
- Bone-Muscle Research Center, College of Nursing and Health Innovation, University of Texas, Arlington, TX 76019, USA
| | - Mark L. Johnson
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, MO 64108, USA
| | - Ziyue Liu
- Department of Biostatistics and Health Data Science, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - Michael J. Wacker
- Department of Biomedical Sciences, School of Medicine, University of Missouri, Kansas City, MO 64108, USA
| | - Lynda Bonewald
- Department of Orthopaedic Surgery, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
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Villalba-Orero M, Garcia-Pavia P, Lara-Pezzi E. Non-invasive assessment of HFpEF in mouse models: current gaps and future directions. BMC Med 2022; 20:349. [PMID: 36229816 PMCID: PMC9563110 DOI: 10.1186/s12916-022-02546-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 09/01/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Heart failure (HF) with preserved ejection fraction (HFpEF) prevalence is increasing, and large clinical trials have failed to reduce mortality. A major reason for this outcome is the failure to translate results from basic research to the clinics. Evaluation of HFpEF in mouse models requires assessing three major key features defining this complex syndrome: the presence of a preserved left ventricular ejection fraction (LVEF), diastolic dysfunction, and the development of HF. In addition, HFpEF is associated with multiple comorbidities such as systemic arterial hypertension, chronic obstructive pulmonary disease, sleep apnea, diabetes, and obesity; thus, non-cardiac disorders assessment is crucial for a complete phenotype characterization. Non-invasive procedures present unquestionable advantages to maintain animal welfare and enable longitudinal analyses. However, unequivocally determining the presence of HFpEF using these methods remains challenging. MAIN TEXT Transthoracic echocardiography (TTE) represents an invaluable tool in HFpEF diagnosis, allowing evaluation of LVEF, diastolic dysfunction, and lung congestion in mice. Since conventional parameters used to evaluate an abnormal diastole like E/A ratio, isovolumic relaxation time, and E/e' may pose limitations in mice, including advanced TTE techniques to characterize cardiac motion, including an assessment under stress, will improve diagnosis. Patients with HFpEF also show electrical cardiac remodelling and therefore electrocardiography may add valuable information in mouse models to assess chronotropic incompetence and sinoatrial node dysfunction, which are major contributors to exercise intolerance. To complete the non-invasive diagnosis of HF, low aerobic exercise capacity and fatigue using exercise tests, impaired oxygen exchange using metabolic cages, and determination of blood biomarkers can be determined. Finally, since HFpEF patients commonly present non-cardiac pathological conditions, acquisition of systemic and pulmonary arterial pressures, blood glucose levels, and performing glucose tolerance and insulin resistance tests are required for a complete phenotyping. CONCLUSION Identification of reliable models of HFpEF in mice by using proper diagnosis tools is necessary to translate basic research results to the clinics. Determining the presence of several HFpEF indicators and a higher number of abnormal parameters will lead to more reliable evidence of HFpEF.
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Affiliation(s)
- María Villalba-Orero
- Departamento de Medicina y Cirugía Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Av. Puerta de Hierro, s/n, 28040, Madrid, Spain. .,Myocardial Pathophysiology Area, Centro Nacional de Investigaciones Cardiovasculares Carlos III, Melchor Fernández Almagro, 3, 28029, Madrid, Spain. .,Centro de investigación Biomédica en Red Cardiovascular (CIBERCV), Madrid, Spain.
| | - Pablo Garcia-Pavia
- Myocardial Pathophysiology Area, Centro Nacional de Investigaciones Cardiovasculares Carlos III, Melchor Fernández Almagro, 3, 28029, Madrid, Spain.,Centro de investigación Biomédica en Red Cardiovascular (CIBERCV), Madrid, Spain.,Heart Failure and Inherited Cardiac Diseases Unit, Department of Cardiology, Hospital Universitario Puerta de Hierro Majadahonda, IDIPHISA, Madrid, Spain.,Universidad Francisco de Vitoria, Madrid, Spain
| | - Enrique Lara-Pezzi
- Myocardial Pathophysiology Area, Centro Nacional de Investigaciones Cardiovasculares Carlos III, Melchor Fernández Almagro, 3, 28029, Madrid, Spain. .,Centro de investigación Biomédica en Red Cardiovascular (CIBERCV), Madrid, Spain.
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Yang Y, Yang H, Lian X, Yang S, Shen H, Wu S, Wang X, Lyu G. Circulating microRNA: Myocardium-derived prenatal biomarker of ventricular septal defects. Front Genet 2022; 13:899034. [PMID: 36035156 PMCID: PMC9403759 DOI: 10.3389/fgene.2022.899034] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 07/13/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Recently, circulating microRNAs (miRNAs) from maternal blood and amniotic fluid have been used as biomarkers for ventricular septal defect (VSD) diagnosis. However, whether circulating miRNAs are associated with fetal myocardium remains unknown.Methods: Dimethadione (DMO) induced a VSD rat model. The miRNA expression profiles of the myocardium, amniotic fluid and maternal serum were analyzed. Differentially expressed microRNAs (DE-microRNAs) were verified by qRT–PCR. The target gene of miR-1-3p was confirmed by dual luciferase reporter assays. Expression of amniotic fluid-derived DE-microRNAs was verified in clinical samples.Results: MiRNAs were differentially expressed in VSD fetal rats and might be involved in cardiomyocyte differentiation and apoptosis. MiR-1-3p, miR-1b and miR-293-5p were downregulated in the myocardium and upregulated in amniotic fluid/maternal serum. The expression of amniotic fluid-derived DE-microRNAs (miR-1-3p, miR-206 and miR-184) was verified in clinical samples. Dual luciferase reporter assays confirmed that miR-1-3p directly targeted SLC8A1/NCX1.Conclusion: MiR-1-3p, miR-1b and miR-293-5p are downregulated in VSD myocardium and upregulated in circulation and may be released into circulation by cardiomyocytes. MiR-1-3p targets SLC8A1/NCX1 and participates in myocardial apoptosis. MiR-1-3p upregulation in circulation is a direct and powerful indicator of fetal VSD and is expected to serve as a prenatal VSD diagnostic marker.
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Affiliation(s)
- Yiru Yang
- Department of Ultrasound, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, China
| | - Hainan Yang
- Department of Ultrasound, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian, China
| | - Xihua Lian
- Department of Ultrasound, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, China
- Department of Pathology and Biomedical Science, University of Otago, Christchurch, New Zealand
| | - Shuping Yang
- Department of Ultrasound, Zhangzhou Affiliated Hospital of Fujian Medical University, Zhangzhou, Fujian, China
| | - Haolin Shen
- Department of Ultrasound, Zhangzhou Affiliated Hospital of Fujian Medical University, Zhangzhou, Fujian, China
| | - Shufen Wu
- Department of Ultrasound, Zhangzhou Affiliated Hospital of Fujian Medical University, Zhangzhou, Fujian, China
| | - Xiali Wang
- Collaborative Innovation Center for Maternal and Infant Health Service Application Technology, Quanzhou Medical College, Quanzhou, Fujian, China
| | - Guorong Lyu
- Department of Ultrasound, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, China
- Collaborative Innovation Center for Maternal and Infant Health Service Application Technology, Quanzhou Medical College, Quanzhou, Fujian, China
- *Correspondence: Guorong Lyu,
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Ottolia M, John S, Hazan A, Goldhaber JI. The Cardiac Na + -Ca 2+ Exchanger: From Structure to Function. Compr Physiol 2021; 12:2681-2717. [PMID: 34964124 DOI: 10.1002/cphy.c200031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Ca2+ homeostasis is essential for cell function and survival. As such, the cytosolic Ca2+ concentration is tightly controlled by a wide number of specialized Ca2+ handling proteins. One among them is the Na+ -Ca2+ exchanger (NCX), a ubiquitous plasma membrane transporter that exploits the electrochemical gradient of Na+ to drive Ca2+ out of the cell, against its concentration gradient. In this critical role, this secondary transporter guides vital physiological processes such as Ca2+ homeostasis, muscle contraction, bone formation, and memory to name a few. Herein, we review the progress made in recent years about the structure of the mammalian NCX and how it relates to function. Particular emphasis will be given to the mammalian cardiac isoform, NCX1.1, due to the extensive studies conducted on this protein. Given the degree of conservation among the eukaryotic exchangers, the information highlighted herein will provide a foundation for our understanding of this transporter family. We will discuss gene structure, alternative splicing, topology, regulatory mechanisms, and NCX's functional role on cardiac physiology. Throughout this article, we will attempt to highlight important milestones in the field and controversial topics where future studies are required. © 2021 American Physiological Society. Compr Physiol 12:1-37, 2021.
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Affiliation(s)
- Michela Ottolia
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Scott John
- Department of Medicine (Cardiology), UCLA, Los Angeles, California, USA
| | - Adina Hazan
- Smidt Heart Institute, Cedars Sinai Medical Center, Los Angeles, California, USA
| | - Joshua I Goldhaber
- Smidt Heart Institute, Cedars Sinai Medical Center, Los Angeles, California, USA
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Silva VLD, Souza SLBD, Mota GAF, Campos DHS, Melo AB, Vileigas DF, Sant’Ana PG, Coelho PM, Bazan SGZ, Leopoldo AS, Cicogna AC. Cenário Disfuncional dos Principais Componentes Responsáveis pelo Equilíbrio do Trânsito de Cálcio Miocárdico na Insuficiência Cardíaca Induzida por Estenose Aórtica. Arq Bras Cardiol 2021; 118:463-475. [PMID: 35262582 PMCID: PMC8856692 DOI: 10.36660/abc.20200618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 02/24/2021] [Indexed: 01/21/2023] Open
Abstract
Fundamento O remodelamento cardíaco patológico se caracteriza por disfunção diastólica e sistólica, levando à insuficiência cardíaca. Neste contexto, o cenário disfuncional do trânsito de cálcio miocárdico (Ca2+) tem sido pouco estudado. Um modelo experimental de estenose aórtica tem sido extensamente utilizado para aprimorar os conhecimentos sobre os principais mecanismos do remodelamento patológico cardíaco. Objetivo Entender o processo disfuncional dos principais componentes responsáveis pelo equilíbrio do cálcio miocárdico e sua influência sobre a função cardíaca na insuficiência cardíaca induzida pela estenose aórtica. Métodos Ratos Wistar de 21 dias de idade foram distribuídos em dois grupos: controle (placebo; n=28) e estenose aórtica (EaO; n=18). A função cardíaca foi analisada com o ecocardiograma, músculo papilar isolado e cardiomiócitos isolados. No ensaio do músculo papilar, SERCA2a e a atividade do canal de Ca2+ do tipo L foram avaliados. O ensaio de cardiomiócitos isolados avaliou o trânsito de cálcio. A expressão proteica da proteínas do trânsito de cálcio foi analisada com o western blot. Os resultados foram estatisticamente significativos quando p <0,05. Resultados Os músculos papilares e cardiomiócitos dos corações no grupo EaO demonstraram falhas mecânicas. Os ratos com EaO apresentaram menor tempo de pico do Ca2+, menor sensibilidade das miofibrilas do Ca2+, prejuízos nos processos de entrada e recaptura de cálcio pelo retículo sarcoplasmático, bem como disfunção no canal de cálcio do tipo L (CCTL). Além disso, os animais com EaO apresentaram maior expressão de SERCA2a, CCTL e trocador de Na+/Ca2+. Conclusão Insuficiência cardíaca sistólica e diastólica devido à estenose aórtica supravalvular acarretou comprometimento da entrada de Ca2+ celular e inibição da recaptura de cálcio pelo retículo sarcoplasmático devido à disfunção no CCTL e SERCA2a, assim como mudanças no trânsito de cálcio e na expressão das principais proteínas responsáveis pela homeostase de Ca2+ celular.
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9
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Al‐Ahmadi W, Webberley TS, Joseph A, Harris F, Chan Y, Alotibi R, Williams JO, Alahmadi A, Decker T, Hughes TR, Ramji DP. Pro-atherogenic actions of signal transducer and activator of transcription 1 serine 727 phosphorylation in LDL receptor deficient mice via modulation of plaque inflammation. FASEB J 2021; 35:e21892. [PMID: 34569651 PMCID: PMC9549671 DOI: 10.1096/fj.202100571rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/11/2021] [Accepted: 08/17/2021] [Indexed: 11/21/2022]
Abstract
Atherosclerosis is a chronic inflammatory disorder of the vasculature regulated by cytokines. We have previously shown that extracellular signal-regulated kinase-1/2 (ERK1/2) plays an important role in serine 727 phosphorylation of signal transducer and activator of transcription-1 (STAT1) transactivation domain, which is required for maximal interferon-γ signaling, and the regulation of modified LDL uptake by macrophages in vitro. Unfortunately, the roles of ERK1/2 and STAT1 serine 727 phosphorylation in atherosclerosis are poorly understood and were investigated using ERK1 deficient mice (ERK2 knockout mice die in utero) and STAT1 knock-in mice (serine 727 replaced by alanine; STAT1 S727A). Mouse Atherosclerosis RT² Profiler PCR Array analysis showed that ERK1 deficiency and STAT1 S727A modification produced significant changes in the expression of 18 and 49 genes, respectively, in bone marrow-derived macrophages, with 17 common regulated genes that included those that play key roles in inflammation and cell migration. Indeed, ERK1 deficiency and STAT1 S727A modification attenuated chemokine-driven migration of macrophages with the former also impacting proliferation and the latter phagocytosis. In LDL receptor deficient mice fed a high fat diet, both ERK1 deficiency and STAT1 S727A modification produced significant reduction in plaque lipid content, albeit at different time points. The STAT1 S727A modification additionally caused a significant reduction in plaque content of macrophages and CD3 T cells and diet-induced cardiac hypertrophy index. In addition, there was a significant increase in plasma IL-2 levels and a trend toward increase in plasma IL-5 levels. These studies demonstrate important roles of STAT1 S727 phosphorylation in particular in the regulation of atherosclerosis-associated macrophage processes in vitro together with plaque lipid content and inflammation in vivo, and support further assessment of its therapeutical potential.
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Affiliation(s)
| | | | - Alex Joseph
- Cardiff School of BiosciencesCardiff UniversityCardiffUK
| | - Ffion Harris
- Cardiff School of BiosciencesCardiff UniversityCardiffUK
| | - Yee‐Hung Chan
- Cardiff School of BiosciencesCardiff UniversityCardiffUK
| | - Reem Alotibi
- Cardiff School of BiosciencesCardiff UniversityCardiffUK
| | | | - Alaa Alahmadi
- Cardiff School of BiosciencesCardiff UniversityCardiffUK
| | - Thomas Decker
- Department of Microbiology and ImmunologyMax F. Perutz LaboratoriesUniversity of ViennaViennaAustria
| | - Timothy R. Hughes
- Systems Immunity Research InstituteSchool of MedicineCardiff UniversityCardiffUK
| | - Dipak P. Ramji
- Cardiff School of BiosciencesCardiff UniversityCardiffUK
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10
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de las Heras N, Galiana A, Ballesteros S, Olivares-Álvaro E, Fuller PJ, Lahera V, Martín-Fernández B. Proanthocyanidins Maintain Cardiac Ionic Homeostasis in Aldosterone-Induced Hypertension and Heart Failure. Int J Mol Sci 2021; 22:ijms22179602. [PMID: 34502509 PMCID: PMC8431754 DOI: 10.3390/ijms22179602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/31/2021] [Accepted: 08/31/2021] [Indexed: 11/16/2022] Open
Abstract
Excess aldosterone promotes pathological remodeling of the heart and imbalance in cardiac ion homeostasis of sodium, potassium and calcium. Novel treatment with proanthocyanidins in aldosterone-treated rats has resulted in downregulation of cardiac SGK1, the main genomic aldosterone-induced intracellular mediator of ion handling. It therefore follows that proanthocyanidins could be modulating cardiac ion homeostasis in aldosterone-treated rats. Male Wistar rats received aldosterone (1 mg kg−1 day−1) +1% NaCl for three weeks. Half of the animals in each group were simultaneously treated with the proanthocyanidins-rich extract (80% w/w) (PRO80, 5 mg kg−1 day−1). PRO80 prevented cardiac hypertrophy and decreased calcium content. Expression of ion channels (ROMK, NHE1, NKA and NCX1) and calcium transient mediators (CAV1.2, pCaMKII and oxCaMKII) were reduced by PRO80 treatment in aldosterone-treated rats. To conclude, our data indicate that PRO80 may offer an alternative treatment to conventional MR-blockade in the prevention of aldosterone-induced cardiac pathology.
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Affiliation(s)
- Natalia de las Heras
- Department of Physiology, Faculty of Medicine, Plaza Ramón y Cajal, s/n. Universidad Complutense, 28040 Madrid, Spain; (N.d.l.H.); (A.G.); (S.B.); (E.O.-Á.); (V.L.)
| | - Adrián Galiana
- Department of Physiology, Faculty of Medicine, Plaza Ramón y Cajal, s/n. Universidad Complutense, 28040 Madrid, Spain; (N.d.l.H.); (A.G.); (S.B.); (E.O.-Á.); (V.L.)
| | - Sandra Ballesteros
- Department of Physiology, Faculty of Medicine, Plaza Ramón y Cajal, s/n. Universidad Complutense, 28040 Madrid, Spain; (N.d.l.H.); (A.G.); (S.B.); (E.O.-Á.); (V.L.)
| | - Elena Olivares-Álvaro
- Department of Physiology, Faculty of Medicine, Plaza Ramón y Cajal, s/n. Universidad Complutense, 28040 Madrid, Spain; (N.d.l.H.); (A.G.); (S.B.); (E.O.-Á.); (V.L.)
| | - Peter J. Fuller
- Centre for Endocrinology and Metabolism, Hudson Institute of Medical Research, Clayton, VIC 3168, Australia;
| | - Vicente Lahera
- Department of Physiology, Faculty of Medicine, Plaza Ramón y Cajal, s/n. Universidad Complutense, 28040 Madrid, Spain; (N.d.l.H.); (A.G.); (S.B.); (E.O.-Á.); (V.L.)
| | - Beatriz Martín-Fernández
- Department of Physiology, Faculty of Medicine, Plaza Ramón y Cajal, s/n. Universidad Complutense, 28040 Madrid, Spain; (N.d.l.H.); (A.G.); (S.B.); (E.O.-Á.); (V.L.)
- Department of Molecular Biology, Faculty of Biology, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain
- Correspondence: ; Tel.: +34-987-291-000 (ext. 3650)
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11
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Weisbrod D. Small and Intermediate Calcium Activated Potassium Channels in the Heart: Role and Strategies in the Treatment of Cardiovascular Diseases. Front Physiol 2020; 11:590534. [PMID: 33329039 PMCID: PMC7719780 DOI: 10.3389/fphys.2020.590534] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 10/02/2020] [Indexed: 12/11/2022] Open
Abstract
Calcium-activated potassium channels are a heterogeneous family of channels that, despite their different biophysical characteristics, structures, and pharmacological signatures, play a role of transducer between the ubiquitous intracellular calcium signaling and the electric variations of the membrane. Although this family of channels was extensively described in various excitable and non-excitable tissues, an increasing amount of evidences shows their functional role in the heart. This review aims to focus on the physiological role and the contribution of the small and intermediate calcium-activated potassium channels in cardiac pathologies.
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12
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Hasan KM, Friedman TC, Parveen M, Espinoza-Derout J, Bautista F, Razipour MM, Shao XM, Jordan MC, Roos KP, Mahata SK, Sinha-Hikim AP. Electronic cigarettes cause alteration in cardiac structure and function in diet-induced obese mice. PLoS One 2020; 15:e0239671. [PMID: 33002059 PMCID: PMC7529198 DOI: 10.1371/journal.pone.0239671] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 08/30/2020] [Indexed: 11/19/2022] Open
Abstract
In spite of the widespread use of electronic cigarettes, also known as e-cigarettes, and the proposed adverse cardiac effects of nicotine, the detrimental effects of e-cigarettes on the heart are not well known. This study examines the detrimental effects of e-cigarettes with nicotine at doses that yield circulating nicotine and cotinine in the ranges similar to the levels found in habitual smokers, and a high fat diet (HFD) on cardiac structure and function in a commonly used model of diet-induced obesity (DIO). C57BL/6J mice on an HFD were exposed to e-cigarette in the presence (2.4% nicotine) or absence (0% nicotine) of nicotine and saline aerosol for 12 weeks. Echocardiographic data demonstrated a decrease in left ventricular (LV) fractional shortening, LV ejection fraction, and velocity of circumferential fiber shortening (VCF) in mice treated with e-cigarette (2.4% nicotine) compared to e-cigarette (0% nicotine) or saline exposed mice. Cardiomyocytes (CMs) of mice treated with e-cigarette (2.4% nicotine) exhibited LV abnormalities, including lipid accumulation (ventricular steatosis), myofibrillar derangement and destruction, and mitochondrial hypertrophy, as revealed by transmission electron microscopy. The detrimental effects of e-cigarettes (2.4% nicotine) on cardiac structure and function was accompanied by increased oxidative stress, plasma free fatty acid levels, CM apoptosis, and inactivation of AMP-activated protein kinase and activation of its downstream target, acetyl-CoA-carboxylase. Our results indicate profound adverse effects of e-cigarettes (2.4% nicotine) on the heart in obese mice and raise questions about the safety of the nicotine e-cigarettes use.
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Affiliation(s)
- Kamrul M. Hasan
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA, United States of America
- * E-mail: (KMH); (APSH)
| | - Theodore C. Friedman
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA, United States of America
- David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America
| | - Meher Parveen
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA, United States of America
| | - Jorge Espinoza-Derout
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA, United States of America
| | - Francisco Bautista
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA, United States of America
| | - Mohammad M. Razipour
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA, United States of America
| | - Xuesi M. Shao
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA, United States of America
- David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America
| | - Maria C. Jordan
- David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America
| | - Kenneth P. Roos
- David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America
| | - Sushil K. Mahata
- VA San Diego Health Care System and University of California, San Diego, CA, United States of America
| | - Amiya P. Sinha-Hikim
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA, United States of America
- David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America
- * E-mail: (KMH); (APSH)
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13
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Zhang XH, Morad M. Ca 2+ signaling of human pluripotent stem cells-derived cardiomyocytes as compared to adult mammalian cardiomyocytes. Cell Calcium 2020; 90:102244. [PMID: 32585508 PMCID: PMC7483365 DOI: 10.1016/j.ceca.2020.102244] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 12/23/2022]
Abstract
Human induced pluripotent stem cells derived cardiomyocytes (hiPSC-CMs) have been extensively used for in vitro modeling of human cardiovascular disease, drug screening and pharmacotherapy, but little rigorous studies have been reported on their biophysical or Ca2+ signaling properties. There is also considerable concern as to the level of their maturity and whether they can serve as reliable models for adult human cardiac myocytes. Ultrastructural difference such as lack of t-tubular network, their polygonal shapes, disorganized sarcomeric myofilament, and their rhythmic automaticity, among others, have been cited as evidence for immaturity of hiPSC-CMs. In this review, we will deal with Ca2+ signaling, its regulation, and its stage of maturity as compared to the mammalian adult cardiomyocytes. We shall summarize the data on functional aspects of Ca2+signaling and its parameters that include: L-type calcium channel (Cav1.2), ICa-induced Ca2+release, CICR, and its parameters, cardiac Na/Ca exchanger (NCX1), the ryanodine receptors (RyR2), sarco-reticular Ca2+pump, SERCA2a/PLB, and the contribution of mitochondrial Ca2+ to hiPSC-CMs excitation-contraction (EC)-coupling as compared with adult mammalian cardiomyocytes. The comparative studies suggest that qualitatively hiPSC-CMs have similar Ca2+signaling properties as those of adult cardiomyocytes, but quantitative differences do exist. This review, we hope, will allow the readers to judge for themselves to what extent Ca2+signaling of hiPSC-CMs represents the adult form of this signaling pathway, and whether these cells can be used as good models of human cardiomyocytes.
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Affiliation(s)
- Xiao-Hua Zhang
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina, Clemson University, Charleston SC, United States
| | - Martin Morad
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina, Clemson University, Charleston SC, United States.
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14
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Heart failure with preserved ejection fraction: present status and future directions. Exp Mol Med 2019; 51:1-9. [PMID: 31857581 PMCID: PMC6923411 DOI: 10.1038/s12276-019-0323-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 08/01/2019] [Accepted: 08/22/2019] [Indexed: 12/11/2022] Open
Abstract
The clinical importance of heart failure with preserved ejection fraction (HFpEF) has recently become apparent. HFpEF refers to heart failure (HF) symptoms with normal or near-normal cardiac function on echocardiography. Common clinical features of HFpEF include diastolic dysfunction, reduced compliance, and ventricular hypokinesia. HFpEF differs from the better-known HF with reduced ejection fraction (HFrEF). Despite having a "preserved ejection fraction," patients with HFpEF have symptoms such as shortness of breath, excessive tiredness, and limited exercise capability. Furthermore, the mortality rate and cumulative survival rate are as severe in HFpEF as they are in HFrEF. While beta-blockers and renin-angiotensin-aldosterone system modulators can improve the survival rate in HFrEF, no known therapeutic agents show similar effectiveness in HFpEF. Researchers have examined molecular events in the development of HFpEF using small and middle-sized animal models. This review discusses HFpEF with regard to etiology and clinical features and introduces the use of mouse and other animal models of human HFpEF.
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15
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Duerr GD, Heinemann JC, Kley J, Eichhorn L, Frede S, Weisheit C, Wehner S, Bindila L, Lutz B, Zimmer A, Dewald O. Myocardial maladaptation to pressure overload in CB2 receptor-deficient mice. J Mol Cell Cardiol 2019; 133:86-98. [DOI: 10.1016/j.yjmcc.2019.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 06/03/2019] [Accepted: 06/06/2019] [Indexed: 12/31/2022]
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16
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Li MCH, O'Brien TJ, Todaro M, Powell KL. Acquired cardiac channelopathies in epilepsy: Evidence, mechanisms, and clinical significance. Epilepsia 2019; 60:1753-1767. [PMID: 31353444 DOI: 10.1111/epi.16301] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 07/07/2019] [Accepted: 07/07/2019] [Indexed: 12/13/2022]
Abstract
There is growing evidence that cardiac dysfunction in patients with chronic epilepsy could play a pathogenic role in sudden unexpected death in epilepsy (SUDEP). Recent animal studies have revealed that epilepsy secondarily alters the expression of cardiac ion channels alongside abnormal cardiac electrophysiology and remodeling. These molecular findings represent novel evidence for an acquired cardiac channelopathy in epilepsy, distinct from inherited ion channels mutations associated with cardiocerebral phenotypes. Specifically, seizure activity has been shown to alter the messenger RNA (mRNA) and protein expression of voltage-gated sodium channels (Nav 1.1, Nav 1.5), voltage-gated potassium channels (Kv 4.2, Kv 4.3), sodium-calcium exchangers (NCX1), and nonspecific cation-conducting channels (HCN2, HCN4). The pathophysiology may involve autonomic dysfunction and structural cardiac disease, as both are independently associated with epilepsy and ion channel dysregulation. Indeed, in vivo and in vitro studies of cardiac pathology reveal a complex network of signaling pathways and transcription factors regulating ion channel expression in the setting of sympathetic overactivity, cardiac failure, and hypertrophy. Other mechanisms such as circulating inflammatory mediators or exogenous effects of antiepileptic medications lack evidence. Moreover, an acquired cardiac channelopathy may underlie the electrophysiologic cardiac abnormalities seen in chronic epilepsy, potentially contributing to the increased risk of malignant arrhythmias and sudden death. Therefore, further investigation is necessary to establish whether cardiac ion channel dysregulation similarly occurs in patients with epilepsy, and to characterize any pathogenic relationship with SUDEP.
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Affiliation(s)
- Michael C H Li
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia.,Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia
| | - Terence J O'Brien
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia.,Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia
| | - Marian Todaro
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia.,Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia.,Department of Neurology, Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Kim L Powell
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
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17
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Espinoza-Derout J, Hasan KM, Shao XM, Jordan MC, Sims C, Lee DL, Sinha S, Simmons Z, Mtume N, Liu Y, Roos KP, Sinha-Hikim AP, Friedman TC. Chronic intermittent electronic cigarette exposure induces cardiac dysfunction and atherosclerosis in apolipoprotein-E knockout mice. Am J Physiol Heart Circ Physiol 2019; 317:H445-H459. [PMID: 31172811 DOI: 10.1152/ajpheart.00738.2018] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Electronic cigarettes (e-cigarettes), also known as electronic nicotine delivery systems, are a popular alternative to conventional nicotine cigarettes, both among smokers and those who have never smoked. In spite of the widespread use of e-cigarettes and the proposed detrimental cardiac and atherosclerotic effects of nicotine, the effects of e-cigarettes on these systems are not known. In this study, we investigated the cardiovascular and cardiac effects of e-cigarettes with and without nicotine in apolipoprotein-E knockout (ApoE-/-) mice. We developed an e-cigarette exposure model that delivers nicotine in a manner similar to that of human e-cigarettes users. Using commercially available e-cigarettes, bluCig PLUS, ApoE-/- mice were exposed to saline, e-cigarette without nicotine [e-cigarette (0%)], and e-cigarette with 2.4% nicotine [e-cigarette (2.4%)] aerosol for 12 wk. Echocardiographic data show that mice treated with e-cigarette (2.4%) had decreased left ventricular fractional shortening and ejection fraction compared with e-cigarette (0%) and saline. Ventricular transcriptomic analysis revealed changes in genes associated with metabolism, circadian rhythm, and inflammation in e-cigarette (2.4%)-treated ApoE-/- mice. Transmission electron microscopy revealed that cardiomyocytes of mice treated with e-cigarette (2.4%) exhibited ultrastructural abnormalities indicative of cardiomyopathy. Additionally, we observed increased oxidative stress and mitochondrial DNA mutations in mice treated with e-cigarette (2.4%). ApoE-/- mice on e-cigarette (2.4%) had also increased atherosclerotic lesions compared with saline aerosol-treated mice. These results demonstrate adverse effects of e-cigarettes on cardiac function in mice.NEW & NOTEWORTHY The present study is the first to show that mice exposed to nicotine electronic cigarettes (e-cigarettes) have decreased cardiac fractional shortening and ejection fraction in comparison with controls. RNA-seq analysis reveals a proinflammatory phenotype induced by e-cigarettes with nicotine. We also found increased atherosclerosis in the aortic root of mice treated with e-cigarettes with nicotine. Our results show that e-cigarettes with nicotine lead to detrimental effects on the heart that should serve as a warning to e-cigarette users and agencies that regulate them.
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Affiliation(s)
- Jorge Espinoza-Derout
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Kamrul M Hasan
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Xuesi M Shao
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California.,David Geffen School of Medicine at University of California, Los Angeles, California
| | - Maria C Jordan
- David Geffen School of Medicine at University of California, Los Angeles, California
| | - Carl Sims
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Desean L Lee
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Satyesh Sinha
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California.,David Geffen School of Medicine at University of California, Los Angeles, California
| | - Zena Simmons
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Norma Mtume
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Yanjun Liu
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California.,David Geffen School of Medicine at University of California, Los Angeles, California
| | - Kenneth P Roos
- David Geffen School of Medicine at University of California, Los Angeles, California
| | - Amiya P Sinha-Hikim
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California.,David Geffen School of Medicine at University of California, Los Angeles, California
| | - Theodore C Friedman
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California.,David Geffen School of Medicine at University of California, Los Angeles, California
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18
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Schirmer I, Bualeong T, Budde H, Cimiotti D, Appukuttan A, Klein N, Steinwascher P, Reusch P, Mügge A, Meyer R, Ladilov Y, Jaquet K. Soluble adenylyl cyclase: A novel player in cardiac hypertrophy induced by isoprenaline or pressure overload. PLoS One 2018; 13:e0192322. [PMID: 29466442 PMCID: PMC5821345 DOI: 10.1371/journal.pone.0192322] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 01/22/2018] [Indexed: 12/29/2022] Open
Abstract
Aims In contrast to the membrane bound adenylyl cyclases, the soluble adenylyl cyclase (sAC) is activated by bicarbonate and divalent ions including calcium. sAC is located in the cytosol, nuclei and mitochondria of several tissues including cardiac muscle. However, its role in cardiac pathology is poorly understood. Here we investigate whether sAC is involved in hypertrophic growth using two different model systems. Methods and results In isolated adult rat cardiomyocytes hypertrophy was induced by 24 h β1-adrenoceptor stimulation using isoprenaline (ISO) and a β2-adrenoceptor antagonist (ICI118,551). To monitor hypertrophy cell size along with RNA/DNA- and protein/DNA ratios as well as the expression level of α-skeletal actin were analyzed. sAC activity was suppressed either by treatment with its specific inhibitor KH7 or by knockdown. Both pharmacological inhibition and knockdown blunted hypertrophic growth and reduced expression levels of α-skeletal actin in ISO/ICI treated rat cardiomyocytes. To analyze the underlying cellular mechanism expression levels of phosphorylated CREB, B-Raf and Erk1/2 were examined by western blot. The results suggest the involvement of B-Raf, but not of Erk or CREB in the pro-hypertrophic action of sAC. In wild type and sAC knockout mice pressure overload was induced by transverse aortic constriction. Hemodynamics, heart weight and the expression level of the atrial natriuretic peptide were analyzed. In accordance, transverse aortic constriction failed to induce hypertrophy in sAC knockout mice. Mechanistic analysis revealed a potential role of Erk1/2 in TAC-induced hypertrophy. Conclusion Soluble adenylyl cyclase might be a new pivotal player in the cardiac hypertrophic response either to long-term β1-adrenoceptor stimulation or to pressure overload.
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Affiliation(s)
- Ilona Schirmer
- Cardiology, Research Laboratory Molecular Cardiology, BG Bergmannsheil and St. Josef-Hospital, clinics of the Ruhr-University Bochum, Bochum, Germany
| | - Tippaporn Bualeong
- Institute of Physiology II, Hospital of the Friedrich-Wilhelms-University of Bonn, Bonn, Germany
| | - Heidi Budde
- Cardiology, Research Laboratory Molecular Cardiology, BG Bergmannsheil and St. Josef-Hospital, clinics of the Ruhr-University Bochum, Bochum, Germany
| | - Diana Cimiotti
- Cardiology, Research Laboratory Molecular Cardiology, BG Bergmannsheil and St. Josef-Hospital, clinics of the Ruhr-University Bochum, Bochum, Germany
| | - Avinash Appukuttan
- Clinical Pharmacology, Faculty of Medicine, Ruhr-University of Bochum, Bochum, Germany
| | - Nicole Klein
- Cardiology, Research Laboratory Molecular Cardiology, BG Bergmannsheil and St. Josef-Hospital, clinics of the Ruhr-University Bochum, Bochum, Germany
| | - Philip Steinwascher
- Cardiology, Research Laboratory Molecular Cardiology, BG Bergmannsheil and St. Josef-Hospital, clinics of the Ruhr-University Bochum, Bochum, Germany
| | - Peter Reusch
- Clinical Pharmacology, Faculty of Medicine, Ruhr-University of Bochum, Bochum, Germany
| | - Andreas Mügge
- Cardiology, Research Laboratory Molecular Cardiology, BG Bergmannsheil and St. Josef-Hospital, clinics of the Ruhr-University Bochum, Bochum, Germany
| | - Rainer Meyer
- Institute of Physiology II, Hospital of the Friedrich-Wilhelms-University of Bonn, Bonn, Germany
| | - Yury Ladilov
- Clinical Pharmacology, Faculty of Medicine, Ruhr-University of Bochum, Bochum, Germany
| | - Kornelia Jaquet
- Cardiology, Research Laboratory Molecular Cardiology, BG Bergmannsheil and St. Josef-Hospital, clinics of the Ruhr-University Bochum, Bochum, Germany
- * E-mail:
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19
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Chaanine AH, Sreekumaran Nair K, Bergen RH, Klaus K, Guenzel AJ, Hajjar RJ, Redfield MM. Mitochondrial Integrity and Function in the Progression of Early Pressure Overload-Induced Left Ventricular Remodeling. J Am Heart Assoc 2017; 6:e005869. [PMID: 28619984 PMCID: PMC5669187 DOI: 10.1161/jaha.117.005869] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 05/05/2017] [Indexed: 01/25/2023]
Abstract
BACKGROUND Following pressure overload, compensatory concentric left ventricular remodeling (CR) variably transitions to eccentric remodeling (ER) and systolic dysfunction. Mechanisms responsible for this transition are incompletely understood. Here we leverage phenotypic variability in pressure overload-induced cardiac remodeling to test the hypothesis that altered mitochondrial homeostasis and calcium handling occur early in the transition from CR to ER, before overt systolic dysfunction. METHODS AND RESULTS Sprague Dawley rats were subjected to ascending aortic banding, (n=68) or sham procedure (n=5). At 3 weeks post-ascending aortic banding, all rats showed CR (left ventricular volumes < sham). At 8 weeks post-ascending aortic banding, ejection fraction was increased or preserved but 3 geometric phenotypes were evident despite similar pressure overload severity: persistent CR, mild ER, and moderate ER with left ventricular volumes lower than, similar to, and higher than sham, respectively. Relative to sham, CR and mild ER phenotypes displayed increased phospholamban, S16 phosphorylation, reduced sodium-calcium exchanger expression, and increased mitochondrial biogenesis/content and normal oxidative capacity, whereas moderate ER phenotype displayed decreased p-phospholamban, S16, increased sodium-calcium exchanger expression, similar degree of mitochondrial biogenesis/content, and impaired oxidative capacity with unique activation of mitochondrial autophagy and apoptosis markers (BNIP3 and Bax/Bcl-2). CONCLUSIONS After pressure overload, mitochondrial biogenesis and function and calcium handling are enhanced in compensatory CR. The transition to mild ER is associated with decrease in mitochondrial biogenesis and content; however, the progression to moderate ER is associated with enhanced mitochondrial autophagy/apoptosis and impaired mitochondrial function and calcium handling, which precede the onset of overt systolic dysfunction.
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MESH Headings
- Animals
- Aorta/physiopathology
- Aorta/surgery
- Apoptosis
- Apoptosis Regulatory Proteins/metabolism
- Arterial Pressure
- Autophagy
- Calcium/metabolism
- Calcium-Binding Proteins/metabolism
- Disease Models, Animal
- Disease Progression
- Heart Failure/etiology
- Heart Failure/metabolism
- Heart Failure/pathology
- Heart Failure/physiopathology
- Hypertrophy, Left Ventricular/etiology
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/pathology
- Hypertrophy, Left Ventricular/physiopathology
- Ligation
- Mitochondria, Heart/metabolism
- Mitochondria, Heart/pathology
- Organelle Biogenesis
- Phosphorylation
- Rats, Sprague-Dawley
- Ribosomal Proteins/metabolism
- Sodium-Calcium Exchanger/metabolism
- Time Factors
- Ventricular Dysfunction, Left/etiology
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/pathology
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Function, Left
- Ventricular Remodeling
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Affiliation(s)
| | | | - Robert H Bergen
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN
| | | | - Adam J Guenzel
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN
| | - Roger J Hajjar
- Division of Cardiovascular Diseases, Mount Sinai Icahn School of Medicine, New York, NY
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20
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Triggered activity in atrial myocytes is influenced by Na +/Ca 2+ exchanger activity in genetically altered mice. J Mol Cell Cardiol 2016; 101:106-115. [PMID: 27838371 DOI: 10.1016/j.yjmcc.2016.11.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 10/26/2016] [Accepted: 11/08/2016] [Indexed: 02/05/2023]
Abstract
AIMS In atrial fibrillation, increased function of the Na+/Ca2+-exchanger (NCX) is one among several electrical remodeling mechanisms. METHODS/RESULTS Using the patch-clamp- and Ca2+ imaging-methods, we investigated atrial myocytes from NCX-homozygous-overexpressor (OE)- and heterozygous-knockout (KO)-mice and their corresponding wildtypes (WTOE; WTKO). NCX mediated Ca2+ extrusion capacity was reduced in KO and increased in OE. There was no evidence for structural or molecular remodeling. During a proarrhythmic pacing-protocol, the number of low amplitude delayed afterdepolarizations (DADs) was unaltered in OE vs. WTOE and KO vs. WTKO. However, DADs triggered full spontaneous action potentials (sAP) significantly more often in OE vs. WTOE (ratio sAP/DAD: OE:0.18±0.05; WTOE:0.02±0.02; p<0.001). Using the same protocol, a DAD triggered an sAP by tendency less often in KO vs. WTKO (p=0.06) and significantly less often under a more aggressive proarrhythmic protocol (ratio sAP/DAD: KO:0.01±0.003; WT KO: 0.12±0.05; p=0.007). The DAD amplitude was increased in OE vs. WTOE and decreased in KO vs. WTKO. There were no differences in SR-Ca2+-load, the number of spontaneous Ca2+-release-events or IKACh/IK1. CONCLUSIONS Atrial myocytes with increased NCX expression exhibited increased vulnerability towards sAPs while atriomyocytes with reduced NCX expression were protected. The underlying mechanism consists of a modification of the DAD-amplitude by the level of NCX-activity. Thus, although the number of spontaneous Ca2+-releases and therefore DADs is unaltered, the higher DAD-amplitude in OE made a transgression of the voltage-threshold of an sAP more likely. These findings indicate that the level of NCX activity could influence triggered activity in atrial myocytes independent of possible remodeling processes.
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21
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Tyser RC, Miranda AM, Chen CM, Davidson SM, Srinivas S, Riley PR. Calcium handling precedes cardiac differentiation to initiate the first heartbeat. eLife 2016; 5. [PMID: 27725084 PMCID: PMC5059139 DOI: 10.7554/elife.17113] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 09/13/2016] [Indexed: 11/30/2022] Open
Abstract
The mammalian heartbeat is thought to begin just prior to the linear heart tube stage of development. How the initial contractions are established and the downstream consequences of the earliest contractile function on cardiac differentiation and morphogenesis have not been described. Using high-resolution live imaging of mouse embryos, we observed randomly distributed spontaneous asynchronous Ca2+-oscillations (SACOs) in the forming cardiac crescent (stage E7.75) prior to overt beating. Nascent contraction initiated at around E8.0 and was associated with sarcomeric assembly and rapid Ca2+ transients, underpinned by sequential expression of the Na+-Ca2+ exchanger (NCX1) and L-type Ca2+ channel (LTCC). Pharmacological inhibition of NCX1 and LTCC revealed rapid development of Ca2+ handling in the early heart and an essential early role for NCX1 in establishing SACOs through to the initiation of beating. NCX1 blockade impacted on CaMKII signalling to down-regulate cardiac gene expression, leading to impaired differentiation and failed crescent maturation. DOI:http://dx.doi.org/10.7554/eLife.17113.001 The heart is the first organ to form and to begin working in an embryo during pregnancy. It must begin pumping early to supply oxygen and nutrients to the developing embryo. Coordinated contractions of specialised muscle cells in the heart, called cardiomyocytes, generate the force needed to pump blood. The flow of calcium ions into and out of the cardiomyocytes triggers these heartbeats. In addition to triggering heart contractions, calcium ions also act as a messenger that drives changes in which genes are active in the cardiomyocytes and how these cells behave. Scientists commonly think of the first heartbeat as occurring after a tube-like structure forms in the embryo that will eventually develop into the heart. However, it is not yet clear how the first heartbeat starts or how the initial heartbeats affect further heart development. Tyser, Miranda et al. now show that the first heartbeat actually occurs much earlier in embryonic development than widely appreciated. In the experiments, videos of live mouse embryos showed that prior to the first heartbeat the flow of calcium ions between different cardiomyocytes is not synchronised. However, as the heart grows these calcium flows become coordinated leading to the first heartbeat. The heartbeats also become faster as the heart grows. Using drugs to block the movement of calcium ions, Tyser, Miranda et al. also show that a protein called NCX1 is required to trigger the calcium flows prior to the first heartbeat. Moreover, the experiments revealed that these early heartbeats help drive the growth of cardiomyocytes and shape the developing heart. Together, the experiments show that the first heartbeats are essential for normal heart development. Future studies are needed to determine what controls the speed of the first heartbeats, and what organises the calcium flows that trigger the first heartbeat. Such studies may help scientists better understand birth defects of the heart, and may suggest strategies to rebuild hearts that have been damaged by a heart attack or other injury. DOI:http://dx.doi.org/10.7554/eLife.17113.002
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Affiliation(s)
- Richard Cv Tyser
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,The Hatter Cardiovascular Institute, University College London and Medical School, London, United Kingdom
| | - Antonio Ma Miranda
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | | | - Sean M Davidson
- The Hatter Cardiovascular Institute, University College London and Medical School, London, United Kingdom
| | - Shankar Srinivas
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Paul R Riley
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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22
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Blaustein MP, Chen L, Hamlyn JM, Leenen FHH, Lingrel JB, Wier WG, Zhang J. Pivotal role of α2 Na + pumps and their high affinity ouabain binding site in cardiovascular health and disease. J Physiol 2016; 594:6079-6103. [PMID: 27350568 DOI: 10.1113/jp272419] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/18/2016] [Indexed: 12/13/2022] Open
Abstract
Reduced smooth muscle (SM)-specific α2 Na+ pump expression elevates basal blood pressure (BP) and increases BP sensitivity to angiotensin II (Ang II) and dietary NaCl, whilst SM-α2 overexpression lowers basal BP and decreases Ang II/salt sensitivity. Prolonged ouabain infusion induces hypertension in rodents, and ouabain-resistant mutation of the α2 ouabain binding site (α2R/R mice) confers resistance to several forms of hypertension. Pressure overload-induced heart hypertrophy and failure are attenuated in cardio-specific α2 knockout, cardio-specific α2 overexpression and α2R/R mice. We propose a unifying hypothesis that reconciles these apparently disparate findings: brain mechanisms, activated by Ang II and high NaCl, regulate sympathetic drive and a novel neurohumoral pathway mediated by both brain and circulating endogenous ouabain (EO). Circulating EO modulates ouabain-sensitive α2 Na+ pump activity and Ca2+ transporter expression and, via Na+ /Ca2+ exchange, Ca2+ homeostasis. This regulates sensitivity to sympathetic activity, Ca2+ signalling and arterial and cardiac contraction.
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Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
| | - Ling Chen
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Frans H H Leenen
- Hypertension Unit, University of Ottawa Heart Institute, Ottawa, ON, Canada, K1Y 4W7
| | - Jerry B Lingrel
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524, USA
| | - W Gil Wier
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Jin Zhang
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
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23
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Ujihara Y, Iwasaki K, Takatsu S, Hashimoto K, Naruse K, Mohri S, Katanosaka Y. Induced NCX1 overexpression attenuates pressure overload-induced pathological cardiac remodelling. Cardiovasc Res 2016; 111:348-61. [PMID: 27229460 DOI: 10.1093/cvr/cvw113] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 05/22/2016] [Indexed: 11/12/2022] Open
Abstract
AIMS Although increased Na(+)/Ca(2+) exchanger 1 (NCX1) expression is observed during heart failure (HF), the pathological role of NCX1 during the progression of HF remains unclear. We examined alterations of NCX1 expression and activity in hearts after transverse aortic constriction (TAC) surgery and explored whether NCX1 influences pressure overload-induced pathological cardiac remodelling. METHODS AND RESULTS We generated novel transgenic mice in which NCX1 expression is controlled by a cardiac-specific, doxycycline (DOX)-dependent promoter. In the absence of DOX, TAC surgery caused substantial chamber dilation with a gradual decrease in contractility by 16 weeks. Cardiomyocytes showed a decline in contractility with abnormal Ca(2+) handling during excitation-contraction (E-C) coupling. Reduced NCX1 activity was observed 8 weeks after TAC and was still apparent at 17 weeks. Induced NCX1 overexpression by DOX treatment starting 8 weeks after TAC returned NCX1 activity to pre-TAC levels and prevented chamber dilation with cardiac dysfunction. DOX treatment not only upregulated NCX1 expression in TAC-operated hearts but also returned L-type Ca(2+) channel and sarcoplasmic reticulum (SR) Ca(2+) ATPase expression levels to those in sham-operated hearts. In DOX-treated myocytes, contractility, T-tubule integrity, synchrony of Ca(2+) release from the SR, and Ca(2+) handling during E-C coupling was preserved 16 weeks after TAC surgery. In addition, DOX treatment attenuated the down-regulation of survival signalling and up-regulation of apoptosis signalling 16 weeks after TAC surgery. CONCLUSION Induced overexpression of NCX1 attenuated pressure overload-induced pathological cardiac remodelling. Thus, maintaining NCX1 activity may be a potential therapeutic strategy for preventing the progression of HF.
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Affiliation(s)
- Yoshihiro Ujihara
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan Department of Physiology, Kawasaki Medical School, Kurashiki, Japan
| | - Keiichiro Iwasaki
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Satomi Takatsu
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Ken Hashimoto
- Department of Physiology, Kawasaki Medical School, Kurashiki, Japan
| | - Keiji Naruse
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Satoshi Mohri
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan Department of Physiology, Kawasaki Medical School, Kurashiki, Japan
| | - Yuki Katanosaka
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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24
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Murata K, Ishida J, Ishimaru T, Mizukami H, Hamada J, Saito C, Fukamizu A. Lactation Is a Risk Factor of Postpartum Heart Failure in Mice with Cardiomyocyte-specific Apelin Receptor (APJ) Overexpression. J Biol Chem 2016; 291:11241-51. [PMID: 27033703 DOI: 10.1074/jbc.m115.699009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Indexed: 11/06/2022] Open
Abstract
The G protein-coupled receptor APJ and its ligand apelin are highly expressed in cardiovascular tissues and are associated with the regulation of blood pressure and cardiac function. Although accumulating evidence suggests that APJ plays a crucial role in the heart, it remains unclear whether up-regulation of APJ affects cardiac function. Here we generated cardiomyocyte-specific APJ-overexpressing (APJ-TG) mice and investigated the cardiac phenotype in APJ-TG mice. Male and non-pregnant APJ-TG mice showed cardiac hypertrophy, contractile dysfunction, and elevation of B-type natriuretic peptide gene expression in the heart but not cardiac fibrosis and symptoms of heart failure, including breathing abnormality and pleural effusion. We further examined the influence of APJ overexpression in response to physiological stress induced by pregnancy and lactation in the heart. Interestingly, repeating pregnancy and lactation (pregnancy-lactation cycle) exacerbated cardiac hypertrophy and systolic dysfunction and induced cardiac fibrosis, lung congestion, pleural effusion, and abnormal breathing in APJ-TG mice. These data indicate that female APJ-TG mice develop postpartum cardiomyopathy. We showed that lactation, but not parturition, was critical for the onset of postpartum cardiomyopathy in APJ-TG mice. Furthermore, we found that lactating APJ-TG mice showed impaired myocardial angiogenesis and imbalance of pro- and antiangiogenic gene expression in the heart. These results demonstrate that overexpression of APJ in cardiomyocytes has adverse effects on cardiac function in male and non-pregnant mice and that lactation contributes to the development of postpartum cardiomyopathy in the heart with APJ overexpression.
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Affiliation(s)
- Kazuya Murata
- From the Life Science Center, Tsukuba Advanced Research Alliance, and
| | - Junji Ishida
- From the Life Science Center, Tsukuba Advanced Research Alliance, and Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Ten-noudai, Tsukuba, Ibaraki 305-8577, Japan
| | - Tomohiro Ishimaru
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Ten-noudai, Tsukuba, Ibaraki 305-8577, Japan
| | - Hayase Mizukami
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Ten-noudai, Tsukuba, Ibaraki 305-8577, Japan
| | - Juri Hamada
- From the Life Science Center, Tsukuba Advanced Research Alliance, and
| | - Chiaki Saito
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Ten-noudai, Tsukuba, Ibaraki 305-8577, Japan
| | - Akiyoshi Fukamizu
- From the Life Science Center, Tsukuba Advanced Research Alliance, and Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Ten-noudai, Tsukuba, Ibaraki 305-8577, Japan
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25
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Parvatiyar MS, Marshall JL, Nguyen RT, Jordan MC, Richardson VA, Roos KP, Crosbie-Watson RH. Sarcospan Regulates Cardiac Isoproterenol Response and Prevents Duchenne Muscular Dystrophy-Associated Cardiomyopathy. J Am Heart Assoc 2015; 4:JAHA.115.002481. [PMID: 26702077 PMCID: PMC4845268 DOI: 10.1161/jaha.115.002481] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Background Duchenne muscular dystrophy is a fatal cardiac and skeletal muscle disease resulting from mutations in the dystrophin gene. We have previously demonstrated that a dystrophin‐associated protein, sarcospan (SSPN), ameliorated Duchenne muscular dystrophy skeletal muscle degeneration by activating compensatory pathways that regulate muscle cell adhesion (laminin‐binding) to the extracellular matrix. Conversely, loss of SSPN destabilized skeletal muscle adhesion, hampered muscle regeneration, and reduced force properties. Given the importance of SSPN to skeletal muscle, we investigated the consequences of SSPN ablation in cardiac muscle and determined whether overexpression of SSPN into mdx mice ameliorates cardiac disease symptoms associated with Duchenne muscular dystrophy cardiomyopathy. Methods and Results SSPN‐null mice exhibited cardiac enlargement, exacerbated cardiomyocyte hypertrophy, and increased fibrosis in response to β‐adrenergic challenge (isoproterenol; 0.8 mg/day per 2 weeks). Biochemical analysis of SSPN‐null cardiac muscle revealed reduced sarcolemma localization of many proteins with a known role in cardiomyopathy pathogenesis: dystrophin, the sarcoglycans (α‐, δ‐, and γ‐subunits), and β1D integrin. Transgenic overexpression of SSPN in Duchenne muscular dystrophy mice (mdxTG) improved cardiomyofiber cell adhesion, sarcolemma integrity, cardiac functional parameters, as well as increased expression of compensatory transmembrane proteins that mediate attachment to the extracellular matrix. Conclusions SSPN regulates sarcolemmal expression of laminin‐binding complexes that are critical to cardiac muscle function and protects against transient and chronic injury, including inherited cardiomyopathy.
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Affiliation(s)
- Michelle S Parvatiyar
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA (M.S.P., J.L.M., R.T.N., V.A.R., R.H.C.W.) Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, CA (M.S.P., J.L.M., M.C.J., V.A.R., K.P.R., R.H.C.W.)
| | - Jamie L Marshall
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA (M.S.P., J.L.M., R.T.N., V.A.R., R.H.C.W.) Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, CA (M.S.P., J.L.M., M.C.J., V.A.R., K.P.R., R.H.C.W.)
| | - Reginald T Nguyen
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA (M.S.P., J.L.M., R.T.N., V.A.R., R.H.C.W.)
| | - Maria C Jordan
- Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, CA (M.S.P., J.L.M., M.C.J., V.A.R., K.P.R., R.H.C.W.) Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA (M.C.J., K.P.R.)
| | - Vanitra A Richardson
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA (M.S.P., J.L.M., R.T.N., V.A.R., R.H.C.W.) Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, CA (M.S.P., J.L.M., M.C.J., V.A.R., K.P.R., R.H.C.W.)
| | - Kenneth P Roos
- Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, CA (M.S.P., J.L.M., M.C.J., V.A.R., K.P.R., R.H.C.W.) Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA (M.C.J., K.P.R.)
| | - Rachelle H Crosbie-Watson
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA (M.S.P., J.L.M., R.T.N., V.A.R., R.H.C.W.) Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, CA (M.S.P., J.L.M., M.C.J., V.A.R., K.P.R., R.H.C.W.) Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA (R.H.C.W.)
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26
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Kim JO, Song DW, Kwon EJ, Hong SE, Song HK, Min CK, Kim DH. miR-185 plays an anti-hypertrophic role in the heart via multiple targets in the calcium-signaling pathways. PLoS One 2015; 10:e0122509. [PMID: 25767890 PMCID: PMC4358957 DOI: 10.1371/journal.pone.0122509] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 02/11/2015] [Indexed: 01/15/2023] Open
Abstract
MicroRNA (miRNA) is an endogenous non-coding RNA species that either inhibits RNA translation or promotes degradation of target mRNAs. miRNAs often regulate cellular signaling by targeting multiple genes within the pathways. In the present study, using Gene Set Analysis, a useful bioinformatics tool to identify miRNAs with multiple target genes in the same pathways, we identified miR-185 as a key candidate regulator of cardiac hypertrophy. Using a mouse model, we found that miR-185 was significantly down-regulated in myocardial cells during cardiac hypertrophy induced by transverse aortic constriction. To confirm that miR-185 is an anti-hypertrophic miRNA, genetic manipulation studies such as overexpression and knock-down of miR-185 in neonatal rat ventricular myocytes were conducted. The results showed that up-regulation of miR-185 led to anti-hypertrophic effects, while down-regulation led to pro-hypertrophic effects, suggesting that miR-185 has an anti-hypertrophic role in the heart. Our study further identified Camk2d, Ncx1, and Nfatc3 as direct targets of miR-185. The activity of Nuclear Factor of Activated T-cell (NFAT) and calcium/calmodulin-dependent protein kinase II delta (CaMKIIδ) was negatively regulated by miR-185 as assessed by NFAT-luciferase activity and western blotting. The expression of phospho-phospholamban (Thr-17), a marker of CaMKIIδ activity, was also significantly reduced by miR-185. In conclusion, miR-185 effectively blocked cardiac hypertrophy signaling through multiple targets, rendering it a potential drug target for diseases such as heart failure.
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Affiliation(s)
- Jin Ock Kim
- School of Life Sciences and Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea
| | - Dong Woo Song
- School of Life Sciences and Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea
| | - Eun Jeong Kwon
- School of Life Sciences and Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea
| | - Seong-Eui Hong
- School of Life Sciences and Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea
| | - Hong Ki Song
- School of Life Sciences and Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea
| | - Choon Kee Min
- School of Life Sciences and Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea
| | - Do Han Kim
- School of Life Sciences and Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea
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27
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Magi S, Nasti AA, Gratteri S, Castaldo P, Bompadre S, Amoroso S, Lariccia V. Gram-negative endotoxin lipopolysaccharide induces cardiac hypertrophy: Detrimental role of Na+–Ca2+ exchanger. Eur J Pharmacol 2015; 746:31-40. [DOI: 10.1016/j.ejphar.2014.10.054] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 10/22/2014] [Accepted: 10/25/2014] [Indexed: 01/18/2023]
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Locatelli J, de Assis LVM, Isoldi MC. Calcium handling proteins: structure, function, and modulation by exercise. Heart Fail Rev 2014; 19:207-25. [PMID: 23436107 DOI: 10.1007/s10741-013-9373-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Heart failure is a serious public health issue with a growing prevalence, and it is related with the aging of the population. Hypertension is identified as the main precursor of left ventricular hypertrophy and therefore can lead to diastolic dysfunction and heart failure. Scientific studies have confirmed the beneficial effects of the physical exercise by reducing the blood pressure and improving the functional status of the heart in hypertension. Several proteins are involved in the mobilization of calcium during the coupling excitation-contraction process in the heart among those are sarcoplasmic reticulum Ca(2+)-ATPase, phospholamban, calsequestrin, sodium-calcium exchanger, L-type calcium's channel, and ryanodine receptors. Our goal is to address the beneficial effects of exercise on the calcium handling proteins in a heart with hypertension.
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Affiliation(s)
- Jamille Locatelli
- Institute of Exact and Biological Sciences, Federal University of Ouro Preto, Ouro Prêto, Brazil
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29
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Rodriguez JS, Velez Rueda JO, Salas M, Becerra R, Di Carlo MN, Said M, Vittone L, Rinaldi G, Portiansky EL, Mundiña-Weilenmann C, Palomeque J, Mattiazzi A. Increased Na⁺/Ca²⁺ exchanger expression/activity constitutes a point of inflection in the progression to heart failure of hypertensive rats. PLoS One 2014; 9:e96400. [PMID: 24781001 PMCID: PMC4004550 DOI: 10.1371/journal.pone.0096400] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 04/07/2014] [Indexed: 11/19/2022] Open
Abstract
UNLABELLED Spontaneously hypertensive rat (SHR) constitutes a genetic model widely used to study the natural evolution of hypertensive heart disease. Ca²⁺-handling alterations are known to occur in SHR. However, the putative modifications of Ca²⁺-handling proteins during the progression to heart failure (HF) are not well established. Moreover, the role of apoptosis in SHR is controversial. We investigated intracellular Ca²⁺, Ca²⁺-handling proteins and apoptosis in SHR vs. control Wistar rats (W) from 3 to 15 months (mo). Changes associated with the transition to HF (i.e. lung edema and decrease in midwall fractional shortening), occurred at 15 mo in 38% of SHR (SHRF). In SHRF, twitch and caffeine-induced Ca²⁺ transients, significantly decreased relative to 6/9 mo and 15 mo without HF signs. This decrease occurred in association with a decrease in the time constant of caffeine-Ca²⁺ transient decay and an increase in Na⁺/Ca²⁺ exchanger (NCX) abundance (p<0.05) with no changes in SERCA2a expression/activity. An increased Ca²⁺-calmodulin-kinase II activity, associated with an enhancement of apoptosis (TUNEL and Bax/Bcl2) was observed in SHR relative to W from 3 to 15 mo. CONCLUSIONS 1. Apoptosis is an early and persistent event that may contribute to hypertrophic remodeling but would not participate in the contractile impairment of SHRF. 2. The increase in NCX expression/activity, associated with an increase in Ca²⁺ efflux from the cell, constitutes a primary alteration of Ca²⁺-handling proteins in the evolution to HF. 3. No changes in SERCA2a expression/activity are observed when HF signs become evident.
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Affiliation(s)
- Jesica S. Rodriguez
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina
| | - J. Omar Velez Rueda
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina
| | - Margarita Salas
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina
| | - Romina Becerra
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina
| | - Mariano N. Di Carlo
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina
| | - Matilde Said
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina
| | - Leticia Vittone
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina
| | - Gustavo Rinaldi
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina
| | - Enrique L. Portiansky
- Laboratorio de Análisis de Imágenes, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata, Argentina
| | - Cecilia Mundiña-Weilenmann
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina
- * E-mail: (CM-W); (JP)
| | - Julieta Palomeque
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina
- * E-mail: (CM-W); (JP)
| | - Alicia Mattiazzi
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina
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30
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Kandel SM, Roth BJ. Intracellular calcium and the mechanism of the dip in the anodal strength-interval curve in cardiac tissue. Circ J 2014; 78:1127-35. [PMID: 24583915 DOI: 10.1253/circj.cj-13-1261] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND The strength-interval (SI) curve is an important measure of refractoriness in cardiac tissue. The anodal SI curve contains a "dip" in which the S2 threshold increases with interval. Two explanations exist for this dip: (1) electrotonic interaction between regions of depolarization and hyperpolarization; and (2) the sodium-calcium exchange (NCX) current. The goal of this study is to use mathematical modeling to determine which explanation is correct. METHODS AND RESULTS The bidomain model represents cardiac tissue and the Luo-Rudy model describes the active membrane. The SI curve is determined by applying a threshold stimulus at different time intervals after a previous action potential. During space-clamped and equal-anisotropy-ratios simulations, anodal excitation does not occur. During unequal-anisotropy-ratios simulations, electrotonic currents, not membrane currents, are present during the few milliseconds before excitation. The dip disappears with no NCX current, but is present with 50% or 75% reduction of it. The calcium-induced-calcium-release (CICR) current has little effect on the dip. CONCLUSIONS These results indicate that neither the NCX nor the CICR current is responsible for the dip in the anodal SI curve. It is caused by the electrotonic interaction between regions of depolarization and hyperpolarization following the S2 stimulus.
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31
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Wang J, Song J, Gao E, Zhang XQ, Gu T, Yu D, Koch WJ, Feldman AM, Cheung JY. Induced overexpression of phospholemman S68E mutant improves cardiac contractility and mortality after ischemia-reperfusion. Am J Physiol Heart Circ Physiol 2014; 306:H1066-77. [PMID: 24486513 DOI: 10.1152/ajpheart.00861.2013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phospholemman (PLM), when phosphorylated at Ser(68), inhibits cardiac Na+ / Ca2+ exchanger 1 (NCX1) and relieves its inhibition on Na+ -K+ -ATPase. We have engineered mice in which expression of the phosphomimetic PLM S68E mutant was induced when dietary doxycycline was removed at 5 wk. At 8-10 wk, compared with noninduced or wild-type hearts, S68E expression in induced hearts was ∼35-75% that of endogenous PLM, but protein levels of sarco(endo)plasmic reticulum Ca2+ -ATPase, α1- and α2-subunits of Na+ -K+ -ATPase, α1c-subunit of L-type Ca2+ channel, and phosphorylated ryanodine receptor were unchanged. The NCX1 protein level was increased by ∼47% but the NCX1 current was depressed by ∼34% in induced hearts. Isoproterenol had no effect on NCX1 currents but stimulated Na+ -K+ -ATPase currents equally in induced and noninduced myocytes. At baseline, systolic intracellular Ca2+ concentrations ([Ca2+]i), sarcoplasmic reticulum Ca2+ contents, and [Ca(2+)]i transient and contraction amplitudes were similar between induced and noninduced myocytes. Isoproterenol stimulation resulted in much higher systolic [Ca2+]i, sarcoplasmic reticulum Ca2+ content, and [Ca2+]i transient and contraction amplitudes in induced myocytes. Echocardiography and in vivo close-chest catheterization demonstrated similar baseline myocardial function, but isoproterenol induced a significantly higher +dP/dt in induced compared with noninduced hearts. In contrast to the 50% mortality observed in mice constitutively overexpressing the S68E mutant, induced mice had similar survival as wild-type and noninduced mice. After ischemia-reperfusion, despite similar areas at risk and left ventricular infarct sizes, induced mice had significantly higher +dP/dt and -dP/dt and lower perioperative mortality compared with noninduced mice. We propose that phosphorylated PLM may be a novel therapeutic target in ischemic heart disease.
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Affiliation(s)
- JuFang Wang
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
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32
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Ottolia M, Torres N, Bridge JHB, Philipson KD, Goldhaber JI. Na/Ca exchange and contraction of the heart. J Mol Cell Cardiol 2013; 61:28-33. [PMID: 23770352 DOI: 10.1016/j.yjmcc.2013.06.001] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 05/30/2013] [Accepted: 06/04/2013] [Indexed: 12/19/2022]
Abstract
Sodium-calcium exchange (NCX) is the major calcium (Ca) efflux mechanism of ventricular cardiomyocytes. Consequently the exchanger plays a critical role in the regulation of cellular Ca content and hence contractility. Reductions in Ca efflux by the exchanger, such as those produced by elevated intracellular sodium (Na) in response to cardiac glycosides, raise sarcoplasmic reticulum (SR) Ca stores. The result is an increased Ca transient and cardiac contractility. Enhanced Ca efflux activity by the exchanger, for example during heart failure, may reduce diadic cleft Ca and excitation-contraction (EC) coupling gain. This aggravates the impaired contractility associated with SR Ca ATPase dysfunction and reduced SR Ca load in failing heart muscle. Recent data from our laboratories indicate that NCX can also impact the efficiency of EC coupling and contractility independent of SR Ca load through diadic cleft priming with Ca during the upstroke of the action potential. This article is part of a Special Issue entitled "Na(+) Regulation in Cardiac Myocytes".
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Affiliation(s)
- Michela Ottolia
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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33
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Wang J, Gao E, Chan TO, Zhang XQ, Song J, Shang X, Koch WJ, Feldman AM, Cheung JY. Induced overexpression of Na(+)/Ca(2+) exchanger does not aggravate myocardial dysfunction induced by transverse aortic constriction. J Card Fail 2013; 19:60-70. [PMID: 23273595 DOI: 10.1016/j.cardfail.2012.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 11/06/2012] [Accepted: 11/08/2012] [Indexed: 11/30/2022]
Abstract
BACKGROUND Alterations in expression and activity of cardiac Na(+)/Ca(2+) exchanger (NCX1) have been implicated in the pathogenesis of heart failure. METHODS AND RESULTS Using transgenic mice in which expression of rat NCX1 was induced at 5 weeks of age, we performed transverse aortic constriction (TAC) at 8 weeks and examined cardiac and myocyte function at 15-18 weeks after TAC (age 23-26 weeks). TAC induced left ventricular (LV) and myocyte hypertrophy and increased myocardial fibrosis in both wild-type (WT) and NCX1-overexpressed mice. NCX1 and phosphorylated ryanodine receptor expression was increased by TAC, whereas sarco(endo)plasmic reticulum Ca(2+)-ATPase levels were decreased by TAC. Action potential duration was prolonged by TAC, but to a greater extent in NCX1 myocytes. Na(+)/Ca(2+) exchange current was similar between WT-TAC and WT-sham myocytes, but was higher in NCX1-TAC myocytes. Both myocyte contraction and [Ca(2+)](i) transient amplitudes were reduced in WT-TAC myocytes, but restored to WT-sham levels in NCX1-TAC myocytes. Despite improvement in single myocyte contractility and Ca(2+) dynamics, induced NCX1 overexpression in TAC animals did not ameliorate LV hypertrophy, increase ejection fraction, or enhance inotropic (maximal first derivative of LV pressure rise, +dP/dt) responses to isoproterenol. CONCLUSIONS In pressure-overload hypertrophy, induced overexpression of NCX1 corrected myocyte contractile and [Ca(2+)](i) transient abnormalities but did not aggravate or improve myocardial dysfunction.
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Affiliation(s)
- Jufang Wang
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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34
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Touchberry CD, Green TM, Tchikrizov V, Mannix JE, Mao TF, Carney BW, Girgis M, Vincent RJ, Wetmore LA, Dawn B, Bonewald LF, Stubbs JR, Wacker MJ. FGF23 is a novel regulator of intracellular calcium and cardiac contractility in addition to cardiac hypertrophy. Am J Physiol Endocrinol Metab 2013; 304:E863-73. [PMID: 23443925 PMCID: PMC3625783 DOI: 10.1152/ajpendo.00596.2012] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 02/25/2013] [Indexed: 01/01/2023]
Abstract
Fibroblast growth factor 23 (FGF23) is a hormone released primarily by osteocytes that regulates phosphate and vitamin D metabolism. Recent observational studies in humans suggest that circulating FGF23 is independently associated with cardiac hypertrophy and increased mortality, but it is unknown whether FGF23 can directly alter cardiac function. We found that FGF23 significantly increased cardiomyocyte cell size in vitro, the expression of gene markers of cardiac hypertrophy, and total protein content of cardiac muscle. In addition, FGFR1 and FGFR3 mRNA were the most abundantly expressed FGF receptors in cardiomyocytes, and the coreceptor α-klotho was expressed at very low levels. We tested an animal model of chronic kidney disease (Col4a3(-/-) mice) that has elevated serum FGF23. We found elevations in common hypertrophy gene markers in Col4a3(-/-) hearts compared with wild type but did not observe changes in wall thickness or cell size by week 10. However, the Col4a3(-/-) hearts did show reduced fractional shortening (-17%) and ejection fraction (-11%). Acute exposure of primary cardiomyocytes to FGF23 resulted in elevated intracellular Ca(2+) ([Ca(2+)](i); F/F(o) + 86%) which was blocked by verapamil pretreatment. FGF23 also increased ventricular muscle strip contractility (67%), which was inhibited by FGF receptor antagonism. We hypothesize that although FGF23 can acutely increase [Ca(2+)](i), chronically this may lead to decreases in contractile function or stimulate cardiac hypertrophy, as observed with other stress hormones. In conclusion, FGF23 is a novel bone/heart endocrine factor and may be an important mediator of cardiac Ca(2+) regulation and contractile function during chronic kidney disease.
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MESH Headings
- Animals
- Autoantigens/genetics
- Calcium/metabolism
- Cardiomegaly/genetics
- Cardiomegaly/metabolism
- Cardiomegaly/physiopathology
- Collagen Type IV/genetics
- Disease Models, Animal
- Female
- Fibroblast Growth Factor-23
- Fibroblast Growth Factors/genetics
- Fibroblast Growth Factors/metabolism
- Fibroblast Growth Factors/pharmacology
- Glucuronidase/genetics
- Klotho Proteins
- Male
- Mice
- Mice, Inbred Strains
- Mice, Knockout
- Myocardial Contraction/physiology
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/physiology
- Nephritis, Hereditary/genetics
- Nephritis, Hereditary/metabolism
- Nephritis, Hereditary/physiopathology
- Primary Cell Culture
- Receptors, Fibroblast Growth Factor/genetics
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Affiliation(s)
- Chad D Touchberry
- Muscle Biology Group, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA
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35
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Tritsch E, Mallat Y, Lefebvre F, Diguet N, Escoubet B, Blanc J, De Windt LJ, Catalucci D, Vandecasteele G, Li Z, Mericskay M. An SRF/miR-1 axis regulates NCX1 and annexin A5 protein levels in the normal and failing heart. Cardiovasc Res 2013; 98:372-80. [PMID: 23436819 DOI: 10.1093/cvr/cvt042] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS The expression of the sodium/calcium exchanger NCX1 increases during cardiac hypertrophy and heart failure, playing an important role in Ca(2+) extrusion. This increase is presumed to result from stress signalling induced changes in the interplay between transcriptional and post-transcriptional regulations. We aimed to determine the impact of the SRF transcription factor known to regulate the NCX1 promoter and microRNA genes, on the expression of NCX1 mRNA and protein and annexin A5 (AnxA5), a Ca(2+)-binding protein interacting with NCX1 and increased during HF. METHODS AND RESULTS NCX1 mRNA was decreased while the protein was increased in the failing heart of the cardiomyocyte-restricted SRF knock-out mice (SRF(HKO)). The induction of NCX1 mRNA by the pro-hypertrophic drug phenylephrine observed in control mice was abolished in the SRF(HKO) though the protein was strongly increased. AnxA5 protein expression profile paralleled the expression of NCX1 protein in the SRF(HKO). MiR-1, a microRNA regulated by SRF, was decreased in the SRF(HKO) and repressed by phenylephrine. In vitro and in vivo manipulation of miR-1 levels and site-directed mutagenesis showed that NCX1 and AnxA5 mRNAs are targets of miR-1. AnxA5 overexpression slowed down Ca(2+) extrusion during caffeine application in adult rat cardiomyocytes. CONCLUSION Our study reveals the existence of a complex regulatory loop where SRF regulates the transcription of NCX1 and miR-1, which in turn functions as a rheostat limiting the translation of NCX1 and AnxA5 proteins. The decrease of miR-1 and increase of AnxA5 appear as important modulators of NCX1 expression and activity during heart failure.
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Affiliation(s)
- Eva Tritsch
- Department of Aging, Stress and Inflammation , UPMC Univ Paris 6, 7, quai Saint Bernard - BP 256, Paris 75005, France
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36
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Abbasi A, Thamotharan M, Shin BC, Jordan MC, Roos KP, Stahl A, Devaskar SU. Myocardial macronutrient transporter adaptations in the adult pregestational female intrauterine and postnatal growth-restricted offspring. Am J Physiol Endocrinol Metab 2012; 302:E1352-62. [PMID: 22338075 PMCID: PMC3378069 DOI: 10.1152/ajpendo.00539.2011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Associations between exponential childhood growth superimposed on low birth weight and adult onset cardiovascular disease with glucose intolerance/type 2 diabetes mellitus exist in epidemiological investigations. To determine the metabolic adaptations that guard against myocardial failure on subsequent exposure to hypoxia, we compared with controls (CON), the effect of intrauterine (IUGR), postnatal (PNGR), and intrauterine and postnatal (IPGR) calorie and growth restriction (n = 6/group) on myocardial macronutrient transporter (fatty acid and glucose) -mediated uptake in pregestational young female adult rat offspring. A higher myocardial FAT/CD36 protein expression in IUGR, PNGR, and IPGR, with higher FATP1 in IUGR, FATP6 in PNGR, FABP-c in PNGR and IPGR, and no change in GLUT4 of all groups was observed. These adaptive macronutrient transporter protein changes were associated with no change in myocardial [(3)H]bromopalmitate accumulation but a diminution in 2-deoxy-[(14)C]glucose uptake. Examination of the sarcolemmal subfraction revealed higher basal concentrations of FAT/CD36 in PNGR and FATP1 and GLUT4 in IUGR, PNGR, and IPGR vs. CON. Exogenous insulin uniformly further enhanced sarcolemmal association of these macronutrient transporter proteins above that of basal, with the exception of insulin resistance of FATP1 and GLUT4 in IUGR and FAT/CD36 in PNGR. The basal sarcolemmal macronutrient transporter adaptations proved protective against subsequent chronic hypoxic exposure (7 days) only in IUGR and PNGR, with notable deterioration in IPGR and CON of the echocardiographic ejection fraction. We conclude that the IUGR and PNGR pregestational adult female offspring displayed a resistance to insulin-induced translocation of FATP1, GLUT4, or FAT/CD36 to the myocardial sarcolemma due to preexistent higher basal concentrations. This basal adaptation of myocardial macronutrient transporters ensured adequate fatty acid uptake, thereby proving protective against chronic hypoxia-induced myocardial compromise.
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Affiliation(s)
- Afshan Abbasi
- Department of Pediatrics, Division of Neonatology and Developmental Biology, Neonatal Research Center, David Geffen School of Medicine, University of California at Los Angeles, 10833 Le Conte Ave., Los Angeles, CA 90095, USA
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37
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Aurora AB, Mahmoud AI, Luo X, Johnson BA, van Rooij E, Matsuzaki S, Humphries KM, Hill JA, Bassel-Duby R, Sadek HA, Olson EN. MicroRNA-214 protects the mouse heart from ischemic injury by controlling Ca²⁺ overload and cell death. J Clin Invest 2012; 122:1222-32. [PMID: 22426211 PMCID: PMC3314458 DOI: 10.1172/jci59327] [Citation(s) in RCA: 307] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 02/01/2012] [Indexed: 12/17/2022] Open
Abstract
Early reperfusion of ischemic cardiac tissue remains the most effective intervention for improving clinical outcome following myocardial infarction. However, abnormal increases in intracellular Ca²⁺ during myocardial reperfusion can cause cardiomyocyte death and consequent loss of cardiac function, referred to as ischemia/reperfusion (IR) injury. Therapeutic modulation of Ca²⁺ handling provides some cardioprotection against the paradoxical effects of restoring blood flow to the heart, highlighting the significance of Ca²⁺ overload to IR injury. Cardiac IR is also accompanied by dynamic changes in the expression of microRNAs (miRNAs); for example, miR-214 is upregulated during ischemic injury and heart failure, but its potential role in these processes is unknown. Here, we show that genetic deletion of miR-214 in mice causes loss of cardiac contractility, increased apoptosis, and excessive fibrosis in response to IR injury. The cardioprotective roles of miR-214 during IR injury were attributed to repression of the mRNA encoding sodium/calcium exchanger 1 (Ncx1), a key regulator of Ca²⁺ influx; and to repression of several downstream effectors of Ca²⁺ signaling that mediate cell death. These findings reveal a pivotal role for miR-214 as a regulator of cardiomyocyte Ca²⁺ homeostasis and survival during cardiac injury.
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Affiliation(s)
- Arin B. Aurora
- Department of Molecular Biology and
Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA.
miRagen Therapeutics, Boulder, Colorado, USA.
Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Ahmed I. Mahmoud
- Department of Molecular Biology and
Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA.
miRagen Therapeutics, Boulder, Colorado, USA.
Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Xiang Luo
- Department of Molecular Biology and
Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA.
miRagen Therapeutics, Boulder, Colorado, USA.
Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Brett A. Johnson
- Department of Molecular Biology and
Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA.
miRagen Therapeutics, Boulder, Colorado, USA.
Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Eva van Rooij
- Department of Molecular Biology and
Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA.
miRagen Therapeutics, Boulder, Colorado, USA.
Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Satoshi Matsuzaki
- Department of Molecular Biology and
Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA.
miRagen Therapeutics, Boulder, Colorado, USA.
Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Kenneth M. Humphries
- Department of Molecular Biology and
Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA.
miRagen Therapeutics, Boulder, Colorado, USA.
Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Joseph A. Hill
- Department of Molecular Biology and
Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA.
miRagen Therapeutics, Boulder, Colorado, USA.
Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Rhonda Bassel-Duby
- Department of Molecular Biology and
Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA.
miRagen Therapeutics, Boulder, Colorado, USA.
Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Hesham A. Sadek
- Department of Molecular Biology and
Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA.
miRagen Therapeutics, Boulder, Colorado, USA.
Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Eric N. Olson
- Department of Molecular Biology and
Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas, USA.
miRagen Therapeutics, Boulder, Colorado, USA.
Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
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Proarrhythmia in a non-failing murine model of cardiac-specific Na+/Ca 2+ exchanger overexpression: whole heart and cellular mechanisms. Basic Res Cardiol 2012; 107:247. [PMID: 22327339 DOI: 10.1007/s00395-012-0247-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 01/02/2012] [Accepted: 01/22/2012] [Indexed: 10/14/2022]
Abstract
The cardiac Na(+)/Ca(2+) exchanger (NCX) generates an inward electrical current during SR-Ca(2+) release, thus possibly promoting afterdepolarizations of the action potential (AP). We used transgenic mice 12.5 weeks or younger with cardiomyocyte-directed overexpression of NCX (NCX-Tg) to study the proarrhythmic potential and mechanisms of enhanced NCX activity. NCX-Tg exhibited normal echocardiographic left ventricular function and heart/body weight ratio, while the QT interval was prolonged in surface ECG recordings. Langendorff-perfused NCX-Tg, but not wild-type (WT) hearts, developed ventricular tachycardia. APs and ionic currents were measured in isolated cardiomyocytes. Cell capacitance was unaltered between groups. APs were prolonged in NCX-Tg versus WT myocytes along with voltage-activated K(+) currents (K(v)) not being reduced but even increased in amplitude. During abrupt changes in pacing cycle length, early afterdepolarizations (EADs) were frequently recorded in NCX-Tg but not in WT myocytes. Next to EADs, delayed afterdepolarizations (DAD) triggering spontaneous APs (sAPs) occurred in NCX-Tg but not in WT myocytes. To test whether sAPs were associated with spontaneous Ca(2+) release (sCR), Ca(2+) transients were recorded. Despite the absence of sAPs in WT, sCR was observed in myocytes of both genotypes suggesting a facilitated translation of sCR into DADs in NCX-Tg. Moreover, sCR was more frequent in NCX-Tg as compared to WT. Myocardial protein levels of Ca(2+)-handling proteins were not different between groups except the ryanodine receptor (RyR), which was increased in NCX-Tg versus WT. We conclude that NCX overexpression is proarrhythmic in a non-failing environment even in the absence of reduced K(V). The underlying mechanisms are: (1) occurrence of EADs due to delayed repolarization; (2) facilitated translation from sCR into DADs; (3) proneness to sCR possibly caused by altered Ca(2+) handling and/or increased RyR expression.
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Song J, Gao E, Wang J, Zhang XQ, Chan TO, Koch WJ, Shang X, Joseph JI, Peterson BZ, Feldman AM, Cheung JY. Constitutive overexpression of phosphomimetic phospholemman S68E mutant results in arrhythmias, early mortality, and heart failure: potential involvement of Na+/Ca2+ exchanger. Am J Physiol Heart Circ Physiol 2011; 302:H770-81. [PMID: 22081699 DOI: 10.1152/ajpheart.00733.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Expression and activity of cardiac Na(+)/Ca(2+) exchanger (NCX1) are altered in many disease states. We engineered mice in which the phosphomimetic phospholemman S68E mutant (inhibits NCX1 but not Na(+)-K(+)-ATPase) was constitutively overexpressed in a cardiac-specific manner (conS68E). At 4-6 wk, conS68E mice exhibited severe bradycardia, ventricular arrhythmias, increased left ventricular (LV) mass, decreased cardiac output (CO), and ∼50% mortality compared with wild-type (WT) littermates. Protein levels of NCX1, calsequestrin, ryanodine receptor, and α(1)- and α(2)-subunits of Na(+)-K(+)-ATPase were similar, but sarco(endo)plasmic reticulum Ca(2+)-ATPase was lower, whereas L-type Ca(2+) channels were higher in conS68E hearts. Resting membrane potential and action potential amplitude were similar, but action potential duration was dramatically prolonged in conS68E myocytes. Diastolic intracellular Ca(2+) ([Ca(2+)](i)) was higher, [Ca(2+)](i) transient and maximal contraction amplitudes were lower, and half-time of [Ca(2+)](i) transient decline was longer in conS68E myocytes. Intracellular Na(+) reached maximum within 3 min after isoproterenol addition, followed by decline in WT but not in conS68E myocytes. Na(+)/Ca(2+) exchange, L-type Ca(2+), Na(+)-K(+)-ATPase, and depolarization-activated K(+) currents were decreased in conS68E myocytes. At 22 wk, bradycardia and increased LV mass persisted in conS68E survivors. Despite comparable baseline CO, conS68E survivors at 22 wk exhibited decreased chronotropic, inotropic, and lusitropic responses to isoproterenol. We conclude that constitutive overexpression of S68E mutant was detrimental, both in terms of depressed cardiac function and increased arrhythmogenesis.
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Affiliation(s)
- Jianliang Song
- Division of Nephrology, Thomas Jefferson Univ., 833 Chestnut St., Suite 700, Philadelphia, PA 19107, USA
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Sebag IA, Gillis MA, Calderone A, Kasneci A, Meilleur M, Haddad R, Noiles W, Patel B, Chalifour LE. Sex hormone control of left ventricular structure/function: mechanistic insights using echocardiography, expression, and DNA methylation analyses in adult mice. Am J Physiol Heart Circ Physiol 2011; 301:H1706-15. [DOI: 10.1152/ajpheart.00088.2011] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Calcium flux into and out of the sarco(endo)plasmic reticulum is vitally important to cardiac function because the cycle of calcium entry and exit controls contraction and relaxation. Putative estrogen and androgen consensus binding sites near to a CpG island are present in the cardiac calsequestrin 2 (CSQ2) promoter. Cardiomyocytes express sex hormone receptors and respond to sex hormones. We hypothesized that sex hormones control CSQ2 expression in cardiomyocytes and so affect cardiac structure/function. Echocardiographic analysis of male and female C57bl6n mice identified thinner walled and lighter hearts in females and significant concentric remodeling after long-term gonadectomy. CSQ2 and sodium-calcium exchanger-1 (NCX1) expression was significantly increased in female compared with male hearts and decreased postovariectomy. NCX1, but not CSQ2, expression was increased postcastration. CSQ2 expression was reduced when H9c2 cells were cultured in hormone-deficient media; increased when estrogen receptor-α (ERα), estrogen receptor-β (ERβ), or androgen agonists were added; and increased in hearts from ERβ-deficient mice. CSQ2 expression was reduced in mice fed a diet low in the methyl donor folic acid and in cells treated with 5-azadeoxycytidine suggesting an involvement of DNA methylation. DNA methylation in CpG in the CSQ2 CpG island was significantly different in males and females and was additionally changed postgonadectomy. Expression of DNA methyltransferases 1, 3a, and 3b was unchanged. These studies strongly link sex hormone-directed changes in CSQ2 expression to DNA methylation with changed expression correlated with altered left ventricular structure and function.
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Affiliation(s)
- Igal A. Sebag
- Division of Cardiology, Sir Mortimer B. Davis-Jewish General Hospital
| | - Marc-Antoine Gillis
- Institut du Cardiologie de Montréal et le Départements de Physiologie et Pharmacologie, Université de Montréal
| | - Angelino Calderone
- Institut du Cardiologie de Montréal et le Départements de Physiologie et Pharmacologie, Université de Montréal
| | - Amanda Kasneci
- Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital; and
| | - Melissa Meilleur
- Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital; and
| | - Rami Haddad
- Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital; and
| | - William Noiles
- Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital; and
| | - Bhavini Patel
- Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital; and
| | - Lorraine E. Chalifour
- Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital; and
- Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, Québec
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Opposing roles of FoxP1 and Nfat3 in transcriptional control of cardiomyocyte hypertrophy. Mol Cell Biol 2011; 31:3068-80. [PMID: 21606195 DOI: 10.1128/mcb.00925-10] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Cardiac homeostasis is maintained by a balance of growth-promoting and growth-modulating factors. Sustained elevation of calcium signaling can induce cardiac hypertrophy through activation of Nfat family transcription factors. FoxP family transcription factors are known to interact with Nfat proteins and to modulate their transcriptional activities in lymphocytes. We investigated FoxP1 interaction with Nfat3 (Nfatc4) and their effects on transcription of hypertrophy-associated genes in neonatal rat cardiomyocytes. FoxP1-Nfat3 complexes were visualized using bimolecular fluorescence complementation (BiFC) analysis. Calcineurin activation induced FoxP1-Nfat3 BiFC complex formation. Amino acid substitutions in the predicted interaction interface inhibited it. FoxP1 repressed hypertrophy-associated genes (Myh7, Rcan1, Cx43, Anf, and Bnp) and counteracted their activation by constitutively nuclear Nfat3 (cnNfat3). In contrast, FoxP1 activated genes that maintain normal heart functions (Myh6 and p57Kip2) and cnNfat3 counteracted their activation by FoxP1. Amino acid substitutions in FoxP1 or cnNfat3 that inhibited their interaction abrogated the activation of hypertrophy-associated gene transcription by cnNfat3 and the repression of these genes by FoxP1. FoxP1 and Nfat3 co-occupied the promoter regions of hypertrophy-associated genes in neonatal and adult heart tissue. FoxP1 counteracted hypertrophic cardiomyocyte growth, and connexin 43 mislocalization caused by cnNfat3 expression. These data suggest that the opposing transcriptional activities of FoxP1 and Nfat3 maintain cardiomyocyte homeostasis.
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Pott C, Eckardt L, Goldhaber JI. Triple threat: the Na+/Ca2+ exchanger in the pathophysiology of cardiac arrhythmia, ischemia and heart failure. Curr Drug Targets 2011; 12:737-47. [PMID: 21291388 PMCID: PMC4406235 DOI: 10.2174/138945011795378559] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 08/30/2010] [Indexed: 02/02/2023]
Abstract
The Na(+)/Ca(2+) exchanger (NCX) is the main Ca(2+) extrusion mechanism of the cardiac myocyte and thus is crucial for maintaining Ca(2+) homeostasis. It is involved in the regulation of several parameters of cardiac excitation contraction coupling, such as cytosolic Ca(2+) concentration, repolarization and contractility. Increased NCX activity has been identified as a mechanism promoting heart failure, cardiac ischemia and arrhythmia. Transgenic mice as well as pharmacological interventions have been used to support the idea of using NCX inhibition as a future pharmacological strategy to treat cardiovascular disease.
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Affiliation(s)
- Christian Pott
- University Hospital of Muenster, Department of Cardiology and Angiology, Albert-Schweitzer-Str. 33, 48149 Muenster, Germany.
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Perrino C, Gargiulo G, Pironti G, Franzone A, Scudiero L, De Laurentis M, Magliulo F, Ilardi F, Carotenuto G, Schiattarella GG, Esposito G. Cardiovascular effects of treadmill exercise in physiological and pathological preclinical settings. Am J Physiol Heart Circ Physiol 2011; 300:H1983-9. [PMID: 21490325 DOI: 10.1152/ajpheart.00784.2010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Exercise adaptations result from a coordinated response of multiple organ systems, including cardiovascular, pulmonary, endocrine-metabolic, immunologic, and skeletal muscle. Among these, the cardiovascular system is the most directly affected by exercise, and it is responsible for many of the important acute changes occurring during physical training. In recent years, the development of animal models of pathological or physiological cardiac overload has allowed researchers to precisely analyze the complex cardiovascular responses to stress in genetically altered murine models of human cardiovascular disease. The intensity-controlled treadmill exercise represents a well-characterized model of physiological cardiac hypertrophy because of its ability to mimic the typical responses to exercise in humans. In this review, we describe cardiovascular adaptations to treadmill exercise in mice and the most important parameters that can be used to quantify such modifications. Moreover, we discuss how treadmill exercise can be used to perform physiological testing in mouse models of disease and to enlighten the role of specific signaling pathways on cardiac function.
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Affiliation(s)
- Cinzia Perrino
- Div. of Cardiology, Federico II Univ., Via Pansini 5, 80131, Naples, Italy.
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Abstract
Persistent pressure overload can cause cardiac hypertrophy and progressive heart failure (HF). The authors developed a pressure-overload HF model of juvenile mice to study the cardiac response to pressure overload that may be applicable to clinical processes in children. Severe thoracic aortic banding (sTAB) was performed using a 28-gauge needle for 40 juvenile (age, 3 weeks) and 47 adult (age, 6 weeks) C57BL/6 male mice. To monitor the structural and functional changes, M-mode echocardiography was performed for conscious mice that had undergone sTAB and sham operation. Cardiac hypertrophy, dilation, and HF occurred in both juvenile and adult mice after sTAB. Compared with adults, juvenile HF is characterized by greater impairment of ventricular contractility and less hypertrophy. In addition, juvenile mice had significantly higher rates of survival than adult mice during the early postoperative weeks. Consistent with clinical HF seen in children, juvenile banded mice demonstrated a lower growth rate than either adult banded mice or juvenile control mice that had sham operations. The authors first developed a juvenile murine model of pressure-overload HF. Learning the unique characteristics of pressure-overload HF in juveniles should aid in understanding age-specific pathologic changes for HF development in children.
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Nam SJ, Han SH, Kim HW, Hyun C. The Cardiac Biomarker Sodium-Calcium Exchanger (NCX-1) Can Differentiate between Heart Failure and Renal Failure: A Comparative Study of NCX-1 Expression in Dogs with Chronic Mitral Valvular Insufficiency and Azotemia. J Vet Intern Med 2010; 24:1383-7. [DOI: 10.1111/j.1939-1676.2010.0628.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Wehling-Henricks M, Jordan MC, Gotoh T, Grody WW, Roos KP, Tidball JG. Arginine metabolism by macrophages promotes cardiac and muscle fibrosis in mdx muscular dystrophy. PLoS One 2010; 5:e10763. [PMID: 20505827 PMCID: PMC2874011 DOI: 10.1371/journal.pone.0010763] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 04/30/2010] [Indexed: 11/19/2022] Open
Abstract
Background Duchenne muscular dystrophy (DMD) is the most common, lethal disease of childhood. One of 3500 new-born males suffers from this universally-lethal disease. Other than the use of corticosteroids, little is available to affect the relentless progress of the disease, leading many families to use dietary supplements in hopes of reducing the progression or severity of muscle wasting. Arginine is commonly used as a dietary supplement and its use has been reported to have beneficial effects following short-term administration to mdx mice, a genetic model of DMD. However, the long-term effects of arginine supplementation are unknown. This lack of knowledge about the long-term effects of increased arginine metabolism is important because elevated arginine metabolism can increase tissue fibrosis, and increased fibrosis of skeletal muscles and the heart is an important and potentially life-threatening feature of DMD. Methodology We use both genetic and nutritional manipulations to test whether changes in arginase metabolism promote fibrosis and increase pathology in mdx mice. Our findings show that fibrotic lesions in mdx muscle are enriched with arginase-2-expressing macrophages and that muscle macrophages stimulated with cytokines that activate the M2 phenotype show elevated arginase activity and expression. We generated a line of arginase-2-null mutant mdx mice and found that the mutation reduced fibrosis in muscles of 18-month-old mdx mice, and reduced kyphosis that is attributable to muscle fibrosis. We also observed that dietary supplementation with arginine for 17-months increased mdx muscle fibrosis. In contrast, arginine-2 mutation did not reduce cardiac fibrosis or affect cardiac function assessed by echocardiography, although 17-months of dietary supplementation with arginine increased cardiac fibrosis. Long-term arginine treatments did not decrease matrix metalloproteinase-2 or -9 or increase the expression of utrophin, which have been reported as beneficial effects of short-term treatments. Conclusions/Significance Our findings demonstrate that arginine metabolism by arginase promotes fibrosis of muscle in muscular dystrophy and contributes to kyphosis. Our findings also show that long-term, dietary supplementation with arginine exacerbates fibrosis of dystrophic heart and muscles. Thus, commonly-practiced dietary supplementation with arginine by DMD patients has potential risk for increasing pathology when performed for long periods, despite reports of benefits acquired with short-term supplementation.
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Affiliation(s)
- Michelle Wehling-Henricks
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Maria C. Jordan
- Cardiovascular Research Laboratory, Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Tomomi Gotoh
- Department of Molecular Genetics, Kumamoto University School of Medicine, Kumamoto, Japan
| | - Wayne W. Grody
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Pediatrics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Kenneth P. Roos
- Cardiovascular Research Laboratory, Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - James G. Tidball
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Molecular, Cellular and Integrative Physiology Program, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Jordan MC, Henderson SA, Han T, Fishbein MC, Philipson KD, Roos KP. Myocardial function with reduced expression of the sodium-calcium exchanger. J Card Fail 2010; 16:786-96. [PMID: 20797603 DOI: 10.1016/j.cardfail.2010.03.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 03/04/2010] [Accepted: 03/31/2010] [Indexed: 01/08/2023]
Abstract
BACKGROUND The complete removal of the cardiac sodium-calcium exchanger (NCX1) is associated with embryonic lethality, whereas its overexpression is linked to heart failure. To determine whether or not a reduced expression of NCX1 is compatible with normal heart structure and function, we studied 2 knockout (KO) mouse models with reduced levels of NCX1: a heterozygous global KO (HG-KO) with a 50% level of NCX1 expression in all myocytes, and a ventricular-specific KO (V-KO) with NCX1 expression in only 10% to 20% of the myocytes. METHODS AND RESULTS Both groups of mice were evaluated at baseline, after transaortic constriction (TAC), and after acute or chronic beta-adrenergic stimulation. At baseline, the HG-KO mice had smaller hearts and the V-KO mice had larger hearts than their wild-type (WT) controls (P < .05). The HG-KO and their control WT mice had normal responses to TAC and beta-adrenergic stimulation. However, the V-KO group was intolerant to TAC and had a significantly (P < .05) blunted response to beta-adrenergic stimulation as compared with the HG-KO mice and WT controls. Unlike the HG-KO mice, the V-KO mice did not tolerate chronic isoproterenol infusion. Telemetric analysis of the electrocardiogram, body temperature, and activity revealed a normal diurnal rhythm in all groups of mice, but confirmed shorter QT intervals along with increased arrhythmias and reduced R wave to P wave amplitude ratios in the V-KO mice. CONCLUSIONS Though NCX1 can be reduced by half in all myocytes without significant functional alterations, it must be expressed in more than 20% of the myocytes to prevent severe remodeling and heart failure in mouse heart.
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Affiliation(s)
- Maria C Jordan
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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48
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Barwe SP, Jordan MC, Skay A, Inge L, Rajasekaran SA, Wolle D, Johnson CL, Neco P, Fang K, Rozengurt N, Goldhaber JI, Roos KP, Rajasekaran AK. Dysfunction of ouabain-induced cardiac contractility in mice with heart-specific ablation of Na,K-ATPase beta1-subunit. J Mol Cell Cardiol 2009; 47:552-60. [PMID: 19683723 DOI: 10.1016/j.yjmcc.2009.07.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 07/12/2009] [Accepted: 07/16/2009] [Indexed: 01/06/2023]
Abstract
Na,K-ATPase is composed of two essential alpha- and beta-subunits, both of which have multiple isoforms. Evidence indicates that the Na,K-ATPase enzymatic activity as well as its alpha(1), alpha(3) and beta(1) isoforms are reduced in the failing human heart. The catalytic alpha-subunit is the receptor for cardiac glycosides such as digitalis, used for the treatment of congestive heart failure. The role of the Na,K-ATPase beta(1)-subunit (Na,K-beta(1)) in cardiac function is not known. We used Cre/loxP technology to inactivate the Na,K-beta(1) gene exclusively in the ventricular cardiomyocytes. Animals with homozygous Na,K-beta(1) gene excision were born at the expected Mendelian ratio, grew into adulthood, and appeared to be healthy until 10 months of age. At 13-14 months, these mice had 13% higher heart/body weight ratios, and reduced contractility as revealed by echocardiography compared to their wild-type (WT) littermates. Pressure overload by transverse aortic constriction (TAC) in younger mice, resulted in compensated hypertrophy in WT mice, but decompensation in the Na,K-beta(1) KO mice. The young KO survivors of TAC exhibited decreased contractile function and mimicked the effects of the Na,K-beta(1) KO in older mice. Further, we show that intact hearts of Na,K-beta(1) KO anesthetized mice as well as isolated cardiomyocytes were insensitive to ouabain-induced positive inotropy. This insensitivity was associated with a reduction in NCX1, one of the proteins involved in regulating cardiac contractility. In conclusion, our results demonstrate that Na,K-beta(1) plays an essential role in regulating cardiac contractility and that its loss is associated with significant pathophysiology of the heart.
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Affiliation(s)
- Sonali P Barwe
- Nemours Center for Childhood Cancer Research, Alfred I. duPont Hospital for Children, Rockland Center One, 1701 Rockland Road, Wilmington, DE 19803, USA
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Wang J, Chan TO, Zhang XQ, Gao E, Song J, Koch WJ, Feldman AM, Cheung JY. Induced overexpression of Na+/Ca2+ exchanger transgene: altered myocyte contractility, [Ca2+]i transients, SR Ca2+ contents, and action potential duration. Am J Physiol Heart Circ Physiol 2009; 297:H590-601. [PMID: 19525383 DOI: 10.1152/ajpheart.00190.2009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have produced mice in which expression of the rat cardiac Na(+)/Ca(2+) exchanger (NCX1) transgene was switched on when doxycycline was removed from the feed at 5 wk. At 8 to 10 wk, NCX1 expression in induced (Ind) mouse hearts was 2.5-fold higher but protein levels of sarco(endo)plasmic reticulum Ca(2+)-ATPase, alpha(1)- and alpha(2)-subunits of Na(+)-K(+)-ATPase, phospholamban, ryanodine receptor, calsequestrin, and unphosphorylated and phosphorylated phospholemman were unchanged compared with wild-type (WT) or noninduced (non-Ind) hearts. There was no cellular hypertrophy since WT, non-Ind, and Ind myocytes had similar whole cell membrane capacitance. In Ind myocytes, NCX1 current amplitude was approximately 42% higher, L-type Ca(2+) current amplitude was unchanged, and action potential duration was prolonged compared with WT or non-Ind myocytes. Contraction and intracellular Ca(2+) concentration ([Ca(2+)](i)) transient amplitudes in Ind myocytes were lower at 0.6, not different at 1.8, and higher at 5.0 mM extracellular Ca(2+) concentration ([Ca(2+)](o)) compared with WT or non-Ind myocytes. Despite similar Ca(2+) current amplitude and sarcoplasmic reticulum (SR) Ca(2+) uptake, SR Ca(2+) content at 5.0 mM [Ca(2+)](o) was significantly higher in Ind compared with non-Ind myocytes, indicating that NCX1 directly contributed to SR Ca(2+) loading. Echocardiography demonstrated that heart rate, left ventricular mass, ejection fraction, stroke volume, and cardiac output were similar among the three groups of animals. In vivo close-chest catheterization demonstrated similar contractility and relaxation among the three groups of mice, both at baseline and after stimulation with isoproterenol. We conclude that induced expression of NCX1 transgene resulted in altered [Ca(2+)](i) homeostasis, myocyte contractility, and action potential morphology. In addition, heart failure did not occur 3 to 5 wk after NCX1 transgene was induced to be expressed at levels found in diseased hearts.
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Affiliation(s)
- JuFang Wang
- Department of Medicine, Division of Nephrology, Center of Translational Medicine, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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50
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Moon HS, Choi E, Hyun C. The Cardiac Sodium-Calcium Exchanger Gene (NCX-1) is a Potential Canine Cardiac Biomarker of Chronic Mitral Valvular Insufficiency. J Vet Intern Med 2008; 22:1360-5. [DOI: 10.1111/j.1939-1676.2008.0209.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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