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Smolin N, Sivakumaran V, Robia SL. Molecular Dynamics Simulations Suggest Multiple Binding Sites for Phospholamban on SERCA. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.3070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Hashimoto T, Sivakumaran V, Carnicer R, Zhu G, Hahn VS, Bedja D, Recalde A, Duglan D, Channon KM, Casadei B, Kass DA. Tetrahydrobiopterin Protects Against Hypertrophic Heart Disease Independent of Myocardial Nitric Oxide Synthase Coupling. J Am Heart Assoc 2016; 5:e003208. [PMID: 27001967 PMCID: PMC4943286 DOI: 10.1161/jaha.116.003208] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 02/11/2016] [Indexed: 01/09/2023]
Abstract
BACKGROUND Nitric oxide synthase uncoupling occurs under conditions of oxidative stress modifying the enzyme's function so it generates superoxide rather than nitric oxide. Nitric oxide synthase uncoupling occurs with chronic pressure overload, and both are ameliorated by exogenous tetrahydrobiopterin (BH4)-a cofactor required for normal nitric oxide synthase function-supporting a pathophysiological link. Genetically augmenting BH4 synthesis in endothelial cells fails to replicate this benefit, indicating that other cell types dominate the effects of exogenous BH4 administration. We tested whether the primary cellular target of BH4 is the cardiomyocyte or whether other novel mechanisms are invoked. METHODS AND RESULTS Mice with cardiomyocyte-specific overexpression of GTP cyclohydrolase 1 (mGCH1) and wild-type littermates underwent transverse aortic constriction. The mGCH1 mice had markedly increased myocardial BH4 and, unlike wild type, maintained nitric oxide synthase coupling after transverse aortic constriction; however, the transverse aortic constriction-induced abnormalities in cardiac morphology and function were similar in both groups. In contrast, exogenous BH4 supplementation improved transverse aortic constricted hearts in both groups, suppressed multiple inflammatory cytokines, and attenuated infiltration of inflammatory macrophages into the heart early after transverse aortic constriction. CONCLUSIONS BH4 protection against adverse remodeling in hypertrophic cardiac disease is not driven by its prevention of myocardial nitric oxide synthase uncoupling, as presumed previously. Instead, benefits from exogenous BH4 are mediated by a protective effect coupled to suppression of inflammatory pathways and myocardial macrophage infiltration.
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MESH Headings
- Animals
- Anti-Inflammatory Agents/pharmacology
- Biopterins/analogs & derivatives
- Biopterins/pharmacology
- Cardiovascular Agents/pharmacology
- Cytokines/metabolism
- Cytoprotection
- Disease Models, Animal
- GTP Cyclohydrolase/genetics
- GTP Cyclohydrolase/metabolism
- Humans
- Hypertrophy, Left Ventricular/enzymology
- Hypertrophy, Left Ventricular/pathology
- Hypertrophy, Left Ventricular/physiopathology
- Hypertrophy, Left Ventricular/prevention & control
- Inflammation Mediators/metabolism
- Macrophages/drug effects
- Macrophages/metabolism
- Mice, Transgenic
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/enzymology
- Myocytes, Cardiac/pathology
- Nitric Oxide/metabolism
- Nitric Oxide Synthase/metabolism
- Oxidation-Reduction
- Signal Transduction
- Superoxides/metabolism
- Time Factors
- Ventricular Dysfunction, Left/enzymology
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Dysfunction, Left/prevention & control
- Ventricular Function, Left/drug effects
- Ventricular Remodeling/drug effects
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Affiliation(s)
- Toru Hashimoto
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD
| | - Vidhya Sivakumaran
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD
| | | | - Guangshuo Zhu
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD
| | - Virginia S Hahn
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD
| | - Djahida Bedja
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD
| | - Alice Recalde
- Department of Cardiovascular Medicine, University of Oxford, UK
| | - Drew Duglan
- Department of Cardiovascular Medicine, University of Oxford, UK
| | - Keith M Channon
- Department of Cardiovascular Medicine, University of Oxford, UK
| | - Barbara Casadei
- Department of Cardiovascular Medicine, University of Oxford, UK
| | - David A Kass
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD
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Belmonte F, Das S, Sysa-Shah P, Sivakumaran V, Stanley B, Guo X, Paolocci N, Aon MA, Nagane M, Kuppusamy P, Steenbergen C, Gabrielson K. ErbB2 overexpression upregulates antioxidant enzymes, reduces basal levels of reactive oxygen species, and protects against doxorubicin cardiotoxicity. Am J Physiol Heart Circ Physiol 2015; 309:H1271-80. [PMID: 26254336 DOI: 10.1152/ajpheart.00517.2014] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 07/31/2015] [Indexed: 11/22/2022]
Abstract
Levels of the HER2/ErbB2 protein in the heart are upregulated in some women during breast cancer therapy, and these women are at high risk for developing heart dysfunction after sequential treatment with anti-ErbB2/trastuzumab or doxorubicin. Doxorubicin is known to increase oxidative stress in the heart, and thus we considered the possibility that ErbB2 protein influences the status of cardiac antioxidant defenses in cardiomyocytes. In this study, we measured reactive oxygen species (ROS) in cardiac mitochondria and whole hearts from mice with cardiac-specific overexpression of ErbB2 (ErbB2(tg)) and found that, compared with control mice, high levels of ErbB2 in myocardium result in lower levels of ROS in mitochondria (P = 0.0075) and whole hearts (P = 0.0381). Neonatal cardiomyocytes isolated from ErbB2(tg) hearts have lower ROS levels and less cellular death (P < 0.0001) following doxorubicin treatment. Analyzing antioxidant enzyme levels and activities, we found that ErbB2(tg) hearts have increased levels of glutathione peroxidase 1 (GPx1) protein (P < 0.0001) and GPx activity (P = 0.0031) in addition to increased levels of two known GPx activators, c-Abl (P = 0.0284) and Arg (P < 0.0001). Interestingly, although mitochondrial ROS emission is reduced in the ErbB2(tg) hearts, oxygen consumption rates and complex I activity are similar to control littermates. Compared with these in vivo studies, H9c2 cells transfected with ErbB2 showed less cellular toxicity and produced less ROS (P < 0.0001) after doxorubicin treatment but upregulated GR activity (P = 0.0237) instead of GPx. Our study shows that ErbB2-dependent signaling contributes to antioxidant defenses and suggests a novel mechanism by which anticancer therapies involving ErbB2 antagonists can harm myocardial structure and function.
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Affiliation(s)
- Frances Belmonte
- Program in Molecular and Translational Toxicology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Samarjit Das
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Polina Sysa-Shah
- Department of Molecular and Comparative Pathobiology, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Vidhya Sivakumaran
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, Maryland; and
| | - Brian Stanley
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, Maryland; and
| | - Xin Guo
- Department of Molecular and Comparative Pathobiology, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Nazareno Paolocci
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, Maryland; and
| | - Miguel A Aon
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, Maryland; and
| | - Masaki Nagane
- Department of Radiology, EPR Center for the Study of Viable Systems, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Periannan Kuppusamy
- Department of Radiology, EPR Center for the Study of Viable Systems, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Charles Steenbergen
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Kathleen Gabrielson
- Program in Molecular and Translational Toxicology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Molecular and Comparative Pathobiology, Johns Hopkins Medical Institutions, Baltimore, Maryland;
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Kaludercic N, Carpi A, Nagayama T, Sivakumaran V, Zhu G, Lai EW, Bedja D, De Mario A, Chen K, Gabrielson KL, Lindsey ML, Pacak K, Takimoto E, Shih JC, Kass DA, Di Lisa F, Paolocci N. Monoamine oxidase B prompts mitochondrial and cardiac dysfunction in pressure overloaded hearts. Antioxid Redox Signal 2014; 20:267-80. [PMID: 23581564 PMCID: PMC3887464 DOI: 10.1089/ars.2012.4616] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AIMS Monoamine oxidases (MAOs) are mitochondrial flavoenzymes responsible for neurotransmitter and biogenic amines catabolism. MAO-A contributes to heart failure progression via enhanced norepinephrine catabolism and oxidative stress. The potential pathogenetic role of the isoenzyme MAO-B in cardiac diseases is currently unknown. Moreover, it is has not been determined yet whether MAO activation can directly affect mitochondrial function. RESULTS In wild type mice, pressure overload induced by transverse aortic constriction (TAC) resulted in enhanced dopamine catabolism, left ventricular (LV) remodeling, and dysfunction. Conversely, mice lacking MAO-B (MAO-B(-/-)) subjected to TAC maintained concentric hypertrophy accompanied by extracellular signal regulated kinase (ERK)1/2 activation, and preserved LV function, both at early (3 weeks) and late stages (9 weeks). Enhanced MAO activation triggered oxidative stress, and dropped mitochondrial membrane potential in the presence of ATP synthase inhibitor oligomycin both in neonatal and adult cardiomyocytes. The MAO-B inhibitor pargyline completely offset this change, suggesting that MAO activation induces a latent mitochondrial dysfunction, causing these organelles to hydrolyze ATP. Moreover, MAO-dependent aldehyde formation due to inhibition of aldehyde dehydrogenase 2 activity also contributed to alter mitochondrial bioenergetics. INNOVATION Our study unravels a novel role for MAO-B in the pathogenesis of heart failure, showing that both MAO-driven reactive oxygen species production and impaired aldehyde metabolism affect mitochondrial function. CONCLUSION Under conditions of chronic hemodynamic stress, enhanced MAO-B activity is a major determinant of cardiac structural and functional disarrangement. Both increased oxidative stress and the accumulation of aldehyde intermediates are likely liable for these adverse morphological and mechanical changes by directly targeting mitochondria.
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Affiliation(s)
- Nina Kaludercic
- 1 Neuroscience Institute , National Research Council of Italy, Padova, Italy
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Sivakumaran V, Stanley BA, Tocchetti CG, Ballin JD, Caceres V, Zhou L, Keceli G, Rainer PP, Lee DI, Huke S, Ziolo MT, Kranias EG, Toscano JP, Wilson GM, O'Rourke B, Kass DA, Mahaney JE, Paolocci N. HNO enhances SERCA2a activity and cardiomyocyte function by promoting redox-dependent phospholamban oligomerization. Antioxid Redox Signal 2013; 19:1185-97. [PMID: 23919584 PMCID: PMC3785857 DOI: 10.1089/ars.2012.5057] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
AIMS Nitroxyl (HNO) interacts with thiols to act as a redox-sensitive modulator of protein function. It enhances sarcoplasmic reticular Ca(2+) uptake and myofilament Ca(2+) sensitivity, improving cardiac contractility. This activity has led to clinical testing of HNO donors for heart failure. Here we tested whether HNO alters the inhibitory interaction between phospholamban (PLN) and the sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2a) in a redox-dependent manner, improving Ca(2+) handling in isolated myocytes/hearts. RESULTS Ventriculocytes, sarcoplasmic reticulum (SR) vesicles, and whole hearts were isolated from control (wildtype [WT]) or PLN knockout (pln(-/-)) mice. Compared to WT, pln(-/-) myocytes displayed enhanced resting sarcomere shortening, peak Ca(2+) transient, and blunted β-adrenergic responsiveness. HNO stimulated shortening, relaxation, and Ca(2+) transient in WT cardiomyocytes, and evoked positive inotropy/lusitropy in intact hearts. These changes were markedly blunted in pln(-/-) cells/hearts. HNO enhanced SR Ca(2+) uptake in WT but not pln(-/-) SR-vesicles. Spectroscopic studies in insect cell microsomes expressing SERCA2a±PLN showed that HNO increased Ca(2+)-dependent SERCA2a conformational flexibility but only when PLN was present. In cardiomyocytes, HNO achieved this effect by stabilizing PLN in an oligomeric disulfide bond-dependent configuration, decreasing the amount of free inhibitory monomeric PLN available. INNOVATION HNO-dependent redox changes in myocyte PLN oligomerization relieve PLN inhibition of SERCA2a. CONCLUSIONS PLN plays a central role in HNO-induced enhancement of SERCA2a activity, leading to increased inotropy/lusitropy in intact myocytes and hearts. PLN remains physically associated with SERCA2a; however, less monomeric PLN is available resulting in decreased inhibition of the enzyme. These findings offer new avenues to improve Ca(2+) handling in failing hearts.
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Affiliation(s)
- Vidhya Sivakumaran
- 1 Division of Cardiology, Johns Hopkins Medical Institutions , Baltimore, Maryland
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Abstract
SIGNIFICANCE The regulation of myocardial function by constitutive nitric oxide synthases (NOS) is important for the maintenance of myocardial Ca(2+) homeostasis, relaxation and distensibility, and protection from arrhythmia and abnormal stress stimuli. However, sustained insults such as diabetes, hypertension, hemodynamic overload, and atrial fibrillation lead to dysfunctional NOS activity with superoxide produced instead of NO and worse pathophysiology. RECENT ADVANCES Major strides in understanding the role of normal and abnormal constitutive NOS in the heart have revealed molecular targets by which NO modulates myocyte function and morphology, the role and nature of post-translational modifications of NOS, and factors controlling nitroso-redox balance. Localized and differential signaling from NOS1 (neuronal) versus NOS3 (endothelial) isoforms are being identified, as are methods to restore NOS function in heart disease. CRITICAL ISSUES Abnormal NOS signaling plays a key role in many cardiac disorders, while targeted modulation may potentially reverse this pathogenic source of oxidative stress. FUTURE DIRECTIONS Improvements in the clinical translation of potent modulators of NOS function/dysfunction may ultimately provide a powerful new treatment for many hearts diseases that are fueled by nitroso-redox imbalance.
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Affiliation(s)
- Ricardo Carnicer
- Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Mark J. Crabtree
- Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Vidhya Sivakumaran
- Division of Cardiology, Department of Medicine, Johns Hopkins University Medical Institutions, Baltimore, Maryland
| | - Barbara Casadei
- Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - David A. Kass
- Division of Cardiology, Department of Medicine, Johns Hopkins University Medical Institutions, Baltimore, Maryland
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Kurdi M, Sivakumaran V, Duhé RJ, Aon MA, Paolocci N, Booz GW. Depletion of cellular glutathione modulates LIF-induced JAK1-STAT3 signaling in cardiac myocytes. Int J Biochem Cell Biol 2012; 44:2106-15. [PMID: 22939972 DOI: 10.1016/j.biocel.2012.08.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 08/10/2012] [Accepted: 08/15/2012] [Indexed: 12/30/2022]
Abstract
Previously we reported that the sesquiterpene lactone parthenolide induces oxidative stress in cardiac myocytes, which blocks Janus kinase (JAK) activation by the interleukin 6 (IL-6)-type cytokines. One implication suggested by this finding is that IL-6 signaling is dependent upon cellular anti-oxidant defenses or redox status. Therefore, the present study was undertaken to directly test the hypothesis that JAK1 signaling by the IL-6-type cytokines in cardiac myocytes is impaired by glutathione (GSH) depletion, since this tripeptide is one of the major anti-oxidant molecules and redox-buffers in cells. Cardiac myocytes were pretreated for 6h with l-buthionine-sulfoximine (BSO) to inhibit GSH synthesis. After 24h, cells were dosed with the IL-6-like cytokine, leukemia inhibitory factor (LIF). BSO treatment decreased GSH levels and dose-dependently attenuated activation of JAK1, Signal Transducer and Activator of Transcription 3 (STAT3), and extracellular signal regulated kinases 1 and 2 (ERK1/2). Addition of glutathione monoethyl ester, which is cleaved intracellularly to GSH, prevented attenuation of LIF-induced JAK1 and STAT3 activation, as did the reductant N-acetyl-cysteine. Unexpectedly, LIF-induced STAT1 activation was unaffected by GSH depletion. Evidence was found that STAT3 is more resistant than STAT1 to intermolecular disulfide bond formation under oxidizing conditions and more likely to retain the monomeric form, suggesting that conformational differences explain the differential effect of GSH depletion on STAT1 and STAT3. Overall, our findings indicate that activation of both JAK1 and STAT3 is redox-sensitive and the character of IL-6 type cytokine signaling in cardiac myocytes is sensitive to changes in the cellular redox status. In cardiac myocytes, activation of STAT1 may be favored over STAT3 under oxidizing conditions due to GSH depletion and/or augmented reactive oxygen species production, such as in ischemia-reperfusion and heart failure.
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Affiliation(s)
- Mazen Kurdi
- Department of Chemistry and Biochemistry, Lebanese University, Rafic Hariri Educational Campus, Hadath, Lebanon.
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AlGhatrif M, Watts VL, Sivakumaran V, Niu X, Halushka M, Miller KL, Vandegaer K, Bedja D, Fox-Talbot K, Bielawska A, Paolocci N, Aja S, Gabrielson KL, Barouch LA. Abstract 159: Beneficial Cardiac Effects of Caloric Restriction in a Murine Model of Obesity Are Attenuated with Age. Circ Res 2012. [DOI: 10.1161/res.111.suppl_1.a159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Introduction:
Obesity is associated with increased myocardial steatosis, cardiac dysfunction, mitochondrial uncoupling, and increased apoptosis. Caloric restriction (CR) in older leptin deficient ob/obobese micefails to reduce cardiac steatosis and apoptosis but improves mitochondrial function. This discordant response to caloric restriction and the role of aging in this process are not well understood.
Methods:
We studied 4 month (younger) and 8 month (older) old ob/ob mice and age matched C57BL/6J controls. In each age group, ob/ob mice were assigned to ad lib (AL-ob) or calorie restriction (CR-ob) for 4 weeks. We performed echocardiograms, myocardial triglyceride assays, Oil Red O staining, LC-MS/MS ceramide species measurements, and Western blots. Whole animal metabolism was measured using indirect calorimetry.
Results:
In younger mice, CR reversed the adverse cardiac effects of obesity by reducing heart weight and ventricular wall thickness, reversing myocardial steatosis measured by myocardial TG assay and Oil red O staining, and upregulating phosphorylation of Akt. This was associated with improvement in diastolic function demonstrated by reduction in isovolumetric relaxation time by echocardiography. In contrast, none of these beneficial changes were observed in the older mice. Whole animal metabolism showed that younger CR-ob mice had decreased respiratory exchange ratio compared to AL-ob, indicating greater reliance on fat as a source of energy. Interestingly, the effect of CR on lipotoxicity measured by the composition of ceramides was similar in both age groups.
Conclusion:
In this model of obesity, aging attenuates the benefits of CR on myocardial structure and function. This may be due to older animals’ decreased ability to reverse myocardial steatosis and/or accumulation of oxidative damage over time, and the loss of Akt activation with age.
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Affiliation(s)
| | | | | | - Xiaolin Niu
- Johns Hopkins Univ Sch of Medicine, Baltimore, MD,
| | | | | | | | | | | | | | | | - Susan Aja
- Johns Hopkins Univ Sch of Medicine, Baltimore, MD,
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Niu X, Watts VL, Cingolani OH, Sivakumaran V, Leyton-Mange JS, Ellis CL, Miller KL, Vandegaer K, Bedja D, Gabrielson KL, Paolocci N, Kass DA, Barouch LA. Cardioprotective effect of beta-3 adrenergic receptor agonism: role of neuronal nitric oxide synthase. J Am Coll Cardiol 2012; 59:1979-87. [PMID: 22624839 DOI: 10.1016/j.jacc.2011.12.046] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 11/07/2011] [Accepted: 12/01/2011] [Indexed: 01/08/2023]
Abstract
OBJECTIVES The aim of this study was to determine whether activation of β3-adrenergic receptor (AR) and downstream signaling of nitric oxide synthase (NOS) isoforms protects the heart from failure and hypertrophy induced by pressure overload. BACKGROUND β3-AR and its downstream signaling pathways are recognized as novel modulators of heart function. Unlike β1- and β2-ARs, β3-ARs are stimulated at high catecholamine concentrations and induce negative inotropic effects, serving as a "brake" to protect the heart from catecholamine overstimulation. METHODS C57BL/6J and neuronal NOS (nNOS) knockout mice were assigned to receive transverse aortic constriction (TAC), BRL37344 (β3 agonist, BRL 0.1 mg/kg/h), or both. RESULTS Three weeks of BRL treatment in wild-type mice attenuated left ventricular dilation and systolic dysfunction, and partially reduced cardiac hypertrophy induced by TAC. This effect was associated with increased nitric oxide production and superoxide suppression. TAC decreased endothelial NOS (eNOS) dimerization, indicating eNOS uncoupling, which was not reversed by BRL treatment. However, nNOS protein expression was up-regulated 2-fold by BRL, and the suppressive effect of BRL on superoxide generation was abrogated by acute nNOS inhibition. Furthermore, BRL cardioprotective effects were actually detrimental in nNOS(-/-) mice. CONCLUSIONS These results are the first to show in vivo cardioprotective effects of β3-AR-specific agonism in pressure overload hypertrophy and heart failure, and support nNOS as the primary downstream NOS isoform in maintaining NO and reactive oxygen species balance in the failing heart.
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Affiliation(s)
- Xiaolin Niu
- Department of Cardiology, Tangdu Hospital, The Fourth Military Medical University, Xinsi Road, Xi'an, China. [corrected]
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Aon MA, Stanley BA, Sivakumaran V, Kembro JM, O'Rourke B, Paolocci N, Cortassa S. Glutathione/thioredoxin systems modulate mitochondrial H2O2 emission: an experimental-computational study. ACTA ACUST UNITED AC 2012; 139:479-91. [PMID: 22585969 PMCID: PMC3362521 DOI: 10.1085/jgp.201210772] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The net emission of hydrogen peroxide (H(2)O(2)) from mitochondria results from the balance between reactive oxygen species (ROS) continuously generated in the respiratory chain and ROS scavenging. The relative contribution of the two major antioxidant systems in the mitochondrial matrix, glutathione (GSH) and thioredoxin (Trx), has not been assessed. In this paper, we examine this key question via combined experimental and theoretical approaches, using isolated heart mitochondria from mouse, rat, and guinea pig. As compared with untreated control mitochondria, selective inhibition of Trx reductase with auranofin along with depletion of GSH with 2,4-dinitrochlorobenzene led to a species-dependent increase in H(2)O(2) emission flux of 17, 11, and 6 fold in state 4 and 15, 7, and 8 fold in state 3 for mouse, rat, and guinea pig mitochondria, respectively. The maximal H(2)O(2) emission as a percentage of the total O(2) consumption flux was 11%/2.3% for mouse in states 4 and 3 followed by 2%/0.25% and 0.74%/0.29% in the rat and guinea pig, respectively. A minimal computational model accounting for the kinetics of GSH/Trx systems was developed and was able to simulate increase in H(2)O(2) emission fluxes when both scavenging systems were inhibited separately or together. Model simulations suggest that GSH/Trx systems act in concert. When the scavenging capacity of either one of them saturates during H(2)O(2) overload, they relieve each other until complete saturation, when maximal ROS emission occurs. Quantitatively, these results converge on the idea that GSH/Trx scavenging systems in mitochondria are both essential for keeping minimal levels of H(2)O(2) emission, especially during state 3 respiration, when the energetic output is maximal. This suggests that the very low levels of H(2)O(2) emission observed during forward electron transport in the respiratory chain are a result of the well-orchestrated actions of the two antioxidant systems working continuously to offset ROS production.
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Affiliation(s)
- Miguel Antonio Aon
- Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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11
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Rainer PP, Doleschal B, Kirk JA, Sivakumaran V, Saad Z, Groschner K, Maechler H, Hoefler G, Bauernhofer T, Samonigg H, Hutterer G, Kass DA, Pieske B, von Lewinski D, Pichler M. Sunitinib causes dose-dependent negative functional effects on myocardium and cardiomyocytes. BJU Int 2012; 110:1455-62. [PMID: 22508007 DOI: 10.1111/j.1464-410x.2012.11134.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVES To examine the acute effects of sunitinib on inotropic function, intracellular Ca(2+) transients, myofilament Ca(2+) sensitivity and generation of reactive oxygen species (ROS) in human multicellular myocardium and isolated mouse cardiomyocytes. To search for microRNAs as suitable biomarkers for indicating toxic cardiac effects. PATIENTS AND METHODS After exposure to sunitinib (0.1-10 µg/mL) developed force, diastolic tension and kinetic variables were assessed in isolated human myocardium. Changes in myocyte sarcomere length, whole-cell calcium transients, myofilament force-Ca(2+) relationship, and ROS generation were examined in isolated ventricular mouse cardiomyocytes. Microarray and realtime-PCR were used to screen for differentially expressed microRNAs in cultured cardiomyocytes that were exposed for 24 h to sunitinib. RESULTS We found that higher concentrations of sunitinib (1 and 10 µg/mL) decreased developed force at 30 minutes 76.9 + 2.8 and 54.5 + 6.3%, compared to 96.1 + 2.6% in controls (P < 0.01). Sunitinib exposure significantly decreased sarcomere shortening and Ca2+ transients. Myofilament Ca(2+) sensitivity was not altered, while ROS levels were significantly increased after exposure to the drug. MicroRNA expression patterns were not altered by sunitinib. CONCLUSIONS Sunitinib elicits a dose-dependent negative inotropic effect in myocardium, accompanied by a decline in intracellular Ca(2+) and increased ROS generation. In clinical practice, these cardiotoxic effects should be considered in cases where cardiac concentrations of sunitinib could be increased.
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Affiliation(s)
- Peter P Rainer
- Division of Cardiology, Department of Internal Medicine, Medical University Graz, Austria
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12
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Ding W, Li Z, Shen X, Martin J, King SB, Sivakumaran V, Paolocci N, Gao WD. Reversal of isoflurane-induced depression of myocardial contraction by nitroxyl via myofilament sensitization to Ca2+. J Pharmacol Exp Ther 2011; 339:825-31. [PMID: 21865439 DOI: 10.1124/jpet.111.185272] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Isoflurane (ISO) is known to depress cardiac contraction. Here, we hypothesized that decreasing myofilament Ca(2+) responsiveness is central to ISO-induced reduction in cardiac force development. Moreover, we also tested whether the nitroxyl (HNO) donor 1-nitrosocyclohexyl acetate (NCA), acting as a myofilament Ca(2+) sensitizer, restores force in the presence of ISO. Trabeculae from the right ventricles of LBN/F1 rats were superfused with Krebs-Henseleit solution at room temperature, and force and intracellular Ca(2+) ([Ca(2+)](i)) were measured. Steady-state activations were achieved by stimulating the muscles at 10 Hz in the presence of ryanodine. The same muscles were chemically skinned with 1% Triton X-100, and the force-Ca(2+) relation measurements were repeated. ISO depressed force in a dose-dependent manner without significantly altering [Ca(2+)](i). At 1.5%, force was reduced over 50%, whereas [Ca(2+)](i) remained unaffected. At 3%, contraction was decreased by ∼75% with [Ca(2+)](i) reduced by only 15%. During steady-state activation, 1.5% ISO depressed maximal Ca(2+)-activated force (F(max)) and increased the [Ca(2+)](i) required for 50% activation (Ca(50)) without affecting the Hill coefficient. After skinning, the same muscles showed similar decreases in F(max) and increases in Ca(50) in the presence of ISO. NCA restored force in the presence of ISO without affecting [Ca(2+)](i). These results show that 1) ISO depresses cardiac force development by decreasing myofilament Ca(2+) responsiveness, and 2) myofilament Ca(2+) sensitization by NCA can effectively restore force development without further increases in [Ca(2+)](i). The present findings have potential translational value because of the efficiency and efficacy of HNO on ISO-induced myocardial contractile dysfunction.
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Affiliation(s)
- Wengang Ding
- Department of Anesthesiology, 2nd Affiliated Hospital, Harbin Medical University, Heilongjiang, China
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Stanley BA, Sivakumaran V, Shi S, McDonald I, Lloyd D, Watson WH, Aon MA, Paolocci N. Thioredoxin reductase-2 is essential for keeping low levels of H(2)O(2) emission from isolated heart mitochondria. J Biol Chem 2011; 286:33669-77. [PMID: 21832082 DOI: 10.1074/jbc.m111.284612] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Respiring mitochondria produce H(2)O(2) continuously. When production exceeds scavenging, H(2)O(2) emission occurs, endangering cell functions. The mitochondrial peroxidase peroxiredoxin-3 reduces H(2)O(2) to water using reducing equivalents from NADPH supplied by thioredoxin-2 (Trx2) and, ultimately, thioredoxin reductase-2 (TrxR2). Here, the contribution of this mitochondrial thioredoxin system to the control of H(2)O(2) emission was studied in isolated mitochondria and cardiomyocytes from mouse or guinea pig heart. Energization of mitochondria by the addition of glutamate/malate resulted in a 10-fold decrease in the ratio of oxidized to reduced Trx2. This shift in redox state was accompanied by an increase in NAD(P)H and was dependent on TrxR2 activity. Inhibition of TrxR2 in isolated mitochondria by auranofin resulted in increased H(2)O(2) emission, an effect that was seen under both forward and reverse electron transport. This effect was independent of changes in NAD(P)H or membrane potential. The effects of auranofin were reproduced in cardiomyocytes; superoxide and H(2)O(2) levels increased, but similarly, there was no effect on NAD(P)H or membrane potential. These data show that energization of mitochondria increases the antioxidant potential of the TrxR2/Trx2 system and that inhibition of TrxR2 results in increased H(2)O(2) emission through a mechanism that is independent of changes in other redox couples.
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Affiliation(s)
- Brian A Stanley
- Division of Cardiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
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Tocchetti CG, Stanley BA, Murray CI, Sivakumaran V, Donzelli S, Mancardi D, Pagliaro P, Gao WD, van Eyk J, Kass DA, Wink DA, Paolocci N. Playing with cardiac "redox switches": the "HNO way" to modulate cardiac function. Antioxid Redox Signal 2011; 14:1687-98. [PMID: 21235349 PMCID: PMC3066693 DOI: 10.1089/ars.2010.3859] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The nitric oxide (NO(•)) sibling, nitroxyl or nitrosyl hydride (HNO), is emerging as a molecule whose pharmacological properties include providing functional support to failing hearts. HNO also preconditions myocardial tissue, protecting it against ischemia-reperfusion injury while exerting vascular antiproliferative actions. In this review, HNO's peculiar cardiovascular assets are discussed in light of its unique chemistry that distinguish HNO from NO(•) as well as from reactive oxygen and nitrogen species such as the hydroxyl radical and peroxynitrite. Included here is a discussion of the possible routes of HNO formation in the myocardium and its chemical targets in the heart. HNO has been shown to have positive inotropic/lusitropic effects under normal and congestive heart failure conditions in animal models. The mechanistic intricacies of the beneficial cardiac effects of HNO are examined in cellular models. In contrast to β-receptor/cyclic adenosine monophosphate/protein kinase A-dependent enhancers of myocardial performance, HNO uses its "thiophylic" nature as a vehicle to interact with redox switches such as cysteines, which are located in key components of the cardiac electromechanical machinery ruling myocardial function. Here, we will briefly review new features of HNO's cardiovascular effects that when combined with its positive inotropic/lusitropic action may render HNO donors an attractive addition to the current therapeutic armamentarium for treating patients with acutely decompensated congestive heart failure.
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Affiliation(s)
- Carlo G Tocchetti
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
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Stanley BA, Shi S, Sivakumaran V, Watson W, Aon M, Paolocci N. The Thioredoxin 2 system Controls H2O2 Emission Flux from Mitochondria. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.2696] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Sivakumaran V, De Arras L, Bermudez J, Bigelow DJ, Mahaney JE. Physical Mechanism of SERCA2a Inhibition by Peroxynitrite. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.1636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Dillon TJ, Hölscher D, Sivakumaran V, Horowitz A, Crowley JN. Kinetics of the reactions of HO with methanol (210–351 K) and with ethanol (216–368 K). Phys Chem Chem Phys 2005; 7:349-55. [DOI: 10.1039/b413961e] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Sivakumaran V, Hölscher D, Dillon TJ, Crowley JN. Reaction between OH and HCHO: temperature dependent rate coefficients (202–399 K) and product pathways (298 K). Phys Chem Chem Phys 2003. [DOI: 10.1039/b306859e] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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