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Masjoan Juncos JX, Nadeem F, Shakil S, El-Husari M, Zafar I, Louch WE, Halade GV, Zaky A, Ahmad A, Ahmad S. Myocardial SERCA2 Protects Against Cardiac Damage and Dysfunction Caused by Inhaled Bromine. J Pharmacol Exp Ther 2024; 390:146-158. [PMID: 38772719 PMCID: PMC11192580 DOI: 10.1124/jpet.123.002084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 05/03/2024] [Accepted: 05/08/2024] [Indexed: 05/23/2024] Open
Abstract
Myocardial sarcoendoplasmic reticulum calcium ATPase 2 (SERCA2) activity is critical for heart function. We have demonstrated that inhaled halogen (chlorine or bromine) gases inactivate SERCA2, impair calcium homeostasis, increase proteolysis, and damage the myocardium ultimately leading to cardiac dysfunction. To further elucidate the mechanistic role of SERCA2 in halogen-induced myocardial damage, we used bromine-exposed cardiac-specific SERCA2 knockout (KO) mice [tamoxifen-administered SERCA2 (flox/flox) Tg (αMHC-MerCreMer) mice] and compared them to the oil-administered controls. We performed echocardiography and hemodynamic analysis to investigate cardiac function 24 hours after bromine (600 ppm for 30 minutes) exposure and measured cardiac injury markers in plasma and proteolytic activity in cardiac tissue and performed electron microscopy of the left ventricle (LV). Cardiac-specific SERCA2 knockout mice demonstrated enhanced toxicity to bromine. Bromine exposure increased ultrastructural damage, perturbed LV shape geometry, and demonstrated acutely increased phosphorylation of phospholamban in the KO mice. Bromine-exposed KO mice revealed significantly enhanced mean arterial pressure and sphericity index and decreased LV end diastolic diameter and LV end systolic pressure when compared with the bromine-exposed control FF mice. Strain analysis showed loss of synchronicity, evidenced by an irregular endocardial shape in systole and irregular vector orientation of contractile motion across different segments of the LV in KO mice, both at baseline and after bromine exposure. These studies underscore the critical role of myocardial SERCA2 in preserving cardiac ultrastructure and function during toxic halogen gas exposures. SIGNIFICANCE STATEMENT: Due to their increased industrial production and transportation, halogens such as chlorine and bromine pose an enhanced risk of exposure to the public. Our studies have demonstrated that inhalation of these halogens leads to the inactivation of cardiopulmonary SERCA2 and results in calcium overload. Using cardiac-specific SERCA2 KO mice, these studies further validated the role of SERCA2 in bromine-induced myocardial injury. These studies highlight the increased susceptibility of individuals with pathological loss of cardiac SERCA2 to the effects of bromine.
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Affiliation(s)
- Juan Xavier Masjoan Juncos
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama (J.X.M.J., F.N., S.S., M.E.-H., I.Z, A.Z., A.A., S.A.); Institute for Experimental Medical Research, Oslo University Hospital and KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (W.E.L.); and Division of Cardiovascular Sciences, University of South Florida, Tampa, Florida (G.V.H.)
| | - Fahad Nadeem
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama (J.X.M.J., F.N., S.S., M.E.-H., I.Z, A.Z., A.A., S.A.); Institute for Experimental Medical Research, Oslo University Hospital and KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (W.E.L.); and Division of Cardiovascular Sciences, University of South Florida, Tampa, Florida (G.V.H.)
| | - Shazia Shakil
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama (J.X.M.J., F.N., S.S., M.E.-H., I.Z, A.Z., A.A., S.A.); Institute for Experimental Medical Research, Oslo University Hospital and KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (W.E.L.); and Division of Cardiovascular Sciences, University of South Florida, Tampa, Florida (G.V.H.)
| | - Malik El-Husari
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama (J.X.M.J., F.N., S.S., M.E.-H., I.Z, A.Z., A.A., S.A.); Institute for Experimental Medical Research, Oslo University Hospital and KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (W.E.L.); and Division of Cardiovascular Sciences, University of South Florida, Tampa, Florida (G.V.H.)
| | - Iram Zafar
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama (J.X.M.J., F.N., S.S., M.E.-H., I.Z, A.Z., A.A., S.A.); Institute for Experimental Medical Research, Oslo University Hospital and KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (W.E.L.); and Division of Cardiovascular Sciences, University of South Florida, Tampa, Florida (G.V.H.)
| | - William E Louch
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama (J.X.M.J., F.N., S.S., M.E.-H., I.Z, A.Z., A.A., S.A.); Institute for Experimental Medical Research, Oslo University Hospital and KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (W.E.L.); and Division of Cardiovascular Sciences, University of South Florida, Tampa, Florida (G.V.H.)
| | - Ganesh V Halade
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama (J.X.M.J., F.N., S.S., M.E.-H., I.Z, A.Z., A.A., S.A.); Institute for Experimental Medical Research, Oslo University Hospital and KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (W.E.L.); and Division of Cardiovascular Sciences, University of South Florida, Tampa, Florida (G.V.H.)
| | - Ahmed Zaky
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama (J.X.M.J., F.N., S.S., M.E.-H., I.Z, A.Z., A.A., S.A.); Institute for Experimental Medical Research, Oslo University Hospital and KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (W.E.L.); and Division of Cardiovascular Sciences, University of South Florida, Tampa, Florida (G.V.H.)
| | - Aftab Ahmad
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama (J.X.M.J., F.N., S.S., M.E.-H., I.Z, A.Z., A.A., S.A.); Institute for Experimental Medical Research, Oslo University Hospital and KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (W.E.L.); and Division of Cardiovascular Sciences, University of South Florida, Tampa, Florida (G.V.H.)
| | - Shama Ahmad
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama (J.X.M.J., F.N., S.S., M.E.-H., I.Z, A.Z., A.A., S.A.); Institute for Experimental Medical Research, Oslo University Hospital and KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (W.E.L.); and Division of Cardiovascular Sciences, University of South Florida, Tampa, Florida (G.V.H.)
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Potential of the Cardiovascular Drug Levosimendan in the Management of Amyotrophic Lateral Sclerosis: An Overview of a Working Hypothesis. J Cardiovasc Pharmacol 2020; 74:389-399. [PMID: 31730560 DOI: 10.1097/fjc.0000000000000728] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Levosimendan is a calcium sensitizer that promotes myocyte contractility through its calcium-dependent interaction with cardiac troponin C. Administered intravenously, it has been used for nearly 2 decades to treat acute and advanced heart failure and to support the heart function in various therapy settings characterized by low cardiac output. Effects of levosimendan on noncardiac muscle suggest a possible new application in the treatment of people with amyotrophic lateral sclerosis (ALS), a neuromuscular disorder characterized by progressive weakness, and eventual paralysis. Previous attempts to improve the muscle response in ALS patients and thereby maintain respiratory function and delay progression of disability have produced some mixed results. Continuing this line of investigation, levosimendan has been shown to enhance in vitro the contractility of the diaphragm muscle fibers of non-ALS patients and to improve in vivo diaphragm neuromuscular efficiency in healthy subjects. Possible positive effects on respiratory function in people with ALS were seen in an exploratory phase 2 study, and a phase 3 clinical trial is now underway to evaluate the potential benefit of an oral form of levosimendan on both respiratory and overall functions in patients with ALS. Here, we will review the various known pharmacologic effects of levosimendan, considering their relevance to people living with ALS.
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Li LL, Wei L, Zhang N, Wei WY, Hu C, Deng W, Tang QZ. Levosimendan Protects against Doxorubicin-Induced Cardiotoxicity by Regulating the PTEN/Akt Pathway. BIOMED RESEARCH INTERNATIONAL 2020; 2020:8593617. [PMID: 32596387 PMCID: PMC7298255 DOI: 10.1155/2020/8593617] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 05/22/2020] [Accepted: 05/23/2020] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND AIMS Myocyte apoptosis plays a critical role in the development of doxorubicin- (DOX-) induced cardiotoxicity. In addition to its cardiotonic effect, laboratory evidence indicates that levosimendan can inhibit apoptosis, but its role in DOX-induced cardiac injury remains unclear. Therefore, the present study is aimed at exploring whether levosimendan could attenuate DOX-induced cardiotoxicity. METHODS Levosimendan (1 mg/kg) was administered to mice through oral gavage once daily for 4 weeks, and the mice were also subjected to an intraperitoneal injection of DOX (5 mg/kg) or saline, once a week for 4 weeks, to create a chronic model of DOX-induced cardiotoxicity. A morphological examination and biochemical analysis were used to evaluate the effects of levosimendan. H9C2 cells were used to verify the protective role of levosimendan in vitro. And an Akt inhibitor was utilized to verify the cardioprotection of levosimendan. RESULTS Levosimendan reduced the cardiac dysfunction and attenuated the myocardial apoptosis induced by DOX in vivo and in vitro. Levosimendan also inhibited the activation of phosphatase and tensin homolog (PTEN) and upregulated P-Akt expression both in vivo and in vitro. And inhibition of Akt abolished the cardioprotection of levosimendan in vitro. CONCLUSION Levosimendan may protect against DOX-induced cardiotoxicity via modulation of the PTEN/Akt signaling pathway.
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Affiliation(s)
- Ling-Li Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China
- Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, China
| | - Li Wei
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China
- Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, China
- Department of Pediatrics, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Ning Zhang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China
- Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, China
| | - Wen-Ying Wei
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China
- Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, China
| | - Can Hu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China
- Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, China
| | - Wei Deng
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China
- Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, China
- Department of Cardiology, The Fifth Affiliated Hospital of Xinjiang Medical University, Ürümqi, China
| | - Qi-Zhu Tang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China
- Hubei Key Laboratory of Metabolic and Chronic Diseases, Wuhan 430060, China
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Gonzalez NC, Kuwahira I. Systemic Oxygen Transport with Rest, Exercise, and Hypoxia: A Comparison of Humans, Rats, and Mice. Compr Physiol 2018; 8:1537-1573. [PMID: 30215861 DOI: 10.1002/cphy.c170051] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The objective of this article is to compare and contrast the known characteristics of the systemic O2 transport of humans, rats, and mice at rest and during exercise in normoxia and hypoxia. This analysis should help understand when rodent O2 transport findings can-and cannot-be applied to human responses to similar conditions. The O2 -transport system was analyzed as composed of four linked conductances: ventilation, alveolo-capillary diffusion, circulatory convection, and tissue capillary-cell diffusion. While the mechanisms of O2 transport are similar in the three species, the quantitative differences are naturally large. There are abundant data on total O2 consumption and on ventilatory and pulmonary diffusive conductances under resting conditions in the three species; however, there is much less available information on pulmonary gas exchange, circulatory O2 convection, and tissue O2 diffusion in mice. The scarcity of data largely derives from the difficulty of obtaining blood samples in these small animals and highlights the need for additional research in this area. In spite of the large quantitative differences in absolute and mass-specific O2 flux, available evidence indicates that resting alveolar and arterial and venous blood PO2 values under normoxia are similar in the three species. Additionally, at least in rats, alveolar and arterial blood PO2 under hypoxia and exercise remain closer to the resting values than those observed in humans. This is achieved by a greater ventilatory response, coupled with a closer value of arterial to alveolar PO2 , suggesting a greater efficacy of gas exchange in the rats. © 2018 American Physiological Society. Compr Physiol 8:1537-1573, 2018.
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Affiliation(s)
- Norberto C Gonzalez
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Ichiro Kuwahira
- Department of Pulmonary Medicine, Tokai University School of Medicine, Tokai University Tokyo Hospital, Tokyo, Japan
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Abstract
Mitochondrial dysfunction underlines a multitude of pathologies; however, studies are scarce that rescue the mitochondria for cellular resuscitation. Exploration into the protective role of mitochondrial transcription factor A (TFAM) and its mitochondrial functions respective to cardiomyocyte death are in need of further investigation. TFAM is a gene regulator that acts to mitigate calcium mishandling and ROS production by wrapping around mitochondrial DNA (mtDNA) complexes. TFAM's regulatory functions over serca2a, NFAT, and Lon protease contribute to cardiomyocyte stability. Calcium- and ROS-dependent proteases, calpains, and matrix metalloproteinases (MMPs) are abundantly found upregulated in the failing heart. TFAM's regulatory role over ROS production and calcium mishandling leads to further investigation into the cardioprotective role of exogenous TFAM. In an effort to restabilize physiological and contractile activity of cardiomyocytes in HF models, we propose that TFAM-packed exosomes (TFAM-PE) will act therapeutically by mitigating mitochondrial dysfunction. Notably, this is the first mention of exosomal delivery of transcription factors in the literature. Here we elucidate the role of TFAM in mitochondrial rescue and focus on its therapeutic potential.
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Affiliation(s)
- George H Kunkel
- Department of Physiology and Biophysics, Health Sciences Centre, 1216, School of Medicine, University of Louisville, 500, South Preston Street, Louisville, KY, 40202, USA
| | - Pankaj Chaturvedi
- Department of Physiology and Biophysics, Health Sciences Centre, 1216, School of Medicine, University of Louisville, 500, South Preston Street, Louisville, KY, 40202, USA.
| | - Suresh C Tyagi
- Department of Physiology and Biophysics, Health Sciences Centre, 1216, School of Medicine, University of Louisville, 500, South Preston Street, Louisville, KY, 40202, USA
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Wagner S, Schürmann S, Hein S, Schüttler J, Friedrich O. Septic cardiomyopathy in rat LPS-induced endotoxemia: relative contribution of cellular diastolic Ca(2+) removal pathways, myofibrillar biomechanics properties and action of the cardiotonic drug levosimendan. Basic Res Cardiol 2015; 110:507. [PMID: 26243667 DOI: 10.1007/s00395-015-0507-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 07/13/2015] [Accepted: 07/30/2015] [Indexed: 01/19/2023]
Abstract
Cardiac dysfunction is a common complication in sepsis and is characterized by forward pump failure. Hallmarks of septic cardiomyopathy are decreased myofibrillar contractility and reduced Ca(2+) sensitivity but it is still not clear whether reduced pump efficiency is predominantly a diastolic impairment. Moreover, a comprehensive picture of upstream Ca(2+) handling mechanisms and downstream myosin biomechanical parameters is still missing. Ca(2+)-sensitizing agents in sepsis may be promising but mechanistic insights for drugs like levosimendan are scarce. Here, we used an endotoxemic LPS rat model to study mechanisms of sepsis on in vivo hemodynamics, multicellular myofibrillar Ca(2+) sensitivity, in vitro cellular Ca(2+) homeostasis and subcellular actomyosin interaction with intracardiac catheters, force transducers, confocal Fluo-4 Ca(2+) recordings in paced cardiomyocytes, and in vitro motility assay, respectively. Left ventricular ejection fraction and myofibrillar Ca(2+) sensitivity were depressed in LPS animals but restored by levosimendan. Diastolic Ca(2+) transient kinetics was slowed down by LPS but ameliorated by levosimendan. Selectively blocking intracellular and sarcolemmal Ca(2+) extrusion pathways revealed minor contribution of sarcoplasmic reticulum Ca(2+) ATPase (SERCA) to Ca(2+) transient diastole in LPS-evoked sepsis but rather depressed Na(+)/Ca(2+) exchanger and plasmalemmal Ca(2+) ATPase. This was mostly compensated by levosimendan. Actin sliding velocities were depressed in myosin heart extracts from LPS rats. We conclude that endotoxemia specifically impairs sarcolemmal diastolic Ca(2+) extrusion pathways resulting in intracellular diastolic Ca(2+) overload. Levosimendan, apart from stabilizing Ca(2+)-troponin C complexes, potently improves cellular Ca(2+) extrusion in the septic heart.
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Affiliation(s)
- S Wagner
- Institute of Medical Biotechnology, Friedrich-Alexander-University Erlangen-Nürnberg, Paul-Gordan-Str.3, 91052, Erlangen, Germany
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Regan JA, Mauro AG, Carbone S, Marchetti C, Gill R, Mezzaroma E, Valle Raleigh J, Salloum FN, Van Tassell BW, Abbate A, Toldo S. A mouse model of heart failure with preserved ejection fraction due to chronic infusion of a low subpressor dose of angiotensin II. Am J Physiol Heart Circ Physiol 2015; 309:H771-8. [PMID: 26188021 DOI: 10.1152/ajpheart.00282.2015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 07/11/2015] [Indexed: 01/08/2023]
Abstract
Heart failure (HF) with preserved ejection fraction (HFpEF) is a clinical syndrome of HF symptoms associated with impaired diastolic function. Although it represents ∼50% of patients with HF, the mechanisms of disease are poorly understood, and therapies are generally ineffective in reducing HF progression. Animal models of HFpEF not due to pressure or volume overload are lacking, therefore limiting in-depth understanding of the pathophysiological mechanisms and the development of novel therapies. We hypothesize that a continuous infusion of low-dose angiotensin II (ATII) is sufficient to induce left ventricular (LV) diastolic dysfunction and HFpEF, without increasing blood pressure or inducing LV hypertrophy or dilatation. Osmotic pumps were implanted subcutaneously in 8-wk-old male mice assigned to the ATII (0.2 mg·kg(-1)·day(-1)) or volume-matched vehicle (N = 8/group) for 4 wk. We measured systolic and diastolic arterial blood pressures through a tail-cuff transducer, LV dimensions and ejection fraction through echocardiography, and LV relaxation through pulsed-wave Doppler and LV catheterization. Myocardial fibrosis and cardiomyocyte cross-sectional area were measured. ATII infusion had no effects on systemic arterial blood pressure. ATII induced significant impairment in LV diastolic function, as measured by an increase (worsening) in LV isovolumetric relaxation time, myocardial performance index, isovolumetric relaxation time constant, and LV end-diastolic pressure without altering LV dimensions, mass, or ejection fraction. Chronic infusion of low-dose ATII recapitulates the HFpEF phenotype in the mouse, without increasing systemic arterial blood pressure. This mouse model may provide insight into the mechanisms of HFpEF.
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Affiliation(s)
- Jessica A Regan
- VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia
| | - Adolfo Gabriele Mauro
- VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia; Victoria Johnson Research Center, Virginia Commonwealth University, Richmond, Virginia; and
| | - Salvatore Carbone
- VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia; Victoria Johnson Research Center, Virginia Commonwealth University, Richmond, Virginia; and
| | - Carlo Marchetti
- VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia; Victoria Johnson Research Center, Virginia Commonwealth University, Richmond, Virginia; and
| | - Rabia Gill
- VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia
| | - Eleonora Mezzaroma
- VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia; Victoria Johnson Research Center, Virginia Commonwealth University, Richmond, Virginia; and School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia
| | - Juan Valle Raleigh
- VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia
| | - Fadi N Salloum
- VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia
| | - Benjamin W Van Tassell
- VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia; Victoria Johnson Research Center, Virginia Commonwealth University, Richmond, Virginia; and School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia
| | - Antonio Abbate
- VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia; Victoria Johnson Research Center, Virginia Commonwealth University, Richmond, Virginia; and
| | - Stefano Toldo
- VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia; Victoria Johnson Research Center, Virginia Commonwealth University, Richmond, Virginia; and
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SERCA2 Haploinsufficiency in a Mouse Model of Darier Disease Causes a Selective Predisposition to Heart Failure. BIOMED RESEARCH INTERNATIONAL 2015; 2015:251598. [PMID: 26064889 PMCID: PMC4433638 DOI: 10.1155/2015/251598] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/18/2014] [Accepted: 12/23/2014] [Indexed: 12/28/2022]
Abstract
Null mutations in one copy of ATP2A2, the gene encoding sarco/endoplasmic reticulum Ca(2+)-ATPase isoform 2 (SERCA2), cause Darier disease in humans, a skin condition involving keratinocytes. Cardiac function appears to be unimpaired in Darier disease patients, with no evidence that SERCA2 haploinsufficiency itself causes heart disease. However, SERCA2 deficiency is widely considered a contributing factor in heart failure. We therefore analyzed Atp2a2 heterozygous mice to determine whether SERCA2 haploinsufficiency can exacerbate specific heart disease conditions. Despite reduced SERCA2a levels in heart, Atp2a2 heterozygous mice resembled humans in exhibiting normal cardiac physiology. When subjected to hypothyroidism or crossed with a transgenic model of reduced myofibrillar Ca(2+)-sensitivity, SERCA2 deficiency caused no enhancement of the disease state. However, when combined with a transgenic model of increased myofibrillar Ca(2+)-sensitivity, SERCA2 haploinsufficiency caused rapid onset of hypertrophy, decompensation, and death. These effects were associated with reduced expression of the antiapoptotic Hax1, increased levels of the proapoptotic genes Chop and Casp12, and evidence of perturbations in energy metabolism. These data reveal myofibrillar Ca(2+)-sensitivity to be an important determinant of the cardiac effects of SERCA2 haploinsufficiency and raise the possibility that Darier disease patients are more susceptible to heart failure under certain conditions.
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