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Anatskaya OV, Runov AL, Ponomartsev SV, Vonsky MS, Elmuratov AU, Vinogradov AE. Long-Term Transcriptomic Changes and Cardiomyocyte Hyperpolyploidy after Lactose Intolerance in Neonatal Rats. Int J Mol Sci 2023; 24:ijms24087063. [PMID: 37108224 PMCID: PMC10138443 DOI: 10.3390/ijms24087063] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/02/2023] [Accepted: 04/08/2023] [Indexed: 04/29/2023] Open
Abstract
Many cardiovascular diseases originate from growth retardation, inflammation, and malnutrition during early postnatal development. The nature of this phenomenon is not completely understood. Here we aimed to verify the hypothesis that systemic inflammation triggered by neonatal lactose intolerance (NLI) may exert long-term pathologic effects on cardiac developmental programs and cardiomyocyte transcriptome regulation. Using the rat model of NLI triggered by lactase overloading with lactose and the methods of cytophotometry, image analysis, and mRNA-seq, we evaluated cardiomyocyte ploidy, signs of DNA damage, and NLI-associated long-term transcriptomic changes of genes and gene modules that differed qualitatively (i.e., were switched on or switched off) in the experiment vs. the control. Our data indicated that NLI triggers the long-term animal growth retardation, cardiomyocyte hyperpolyploidy, and extensive transcriptomic rearrangements. Many of these rearrangements are known as manifestations of heart pathologies, including DNA and telomere instability, inflammation, fibrosis, and reactivation of fetal gene program. Moreover, bioinformatic analysis identified possible causes of these pathologic traits, including the impaired signaling via thyroid hormone, calcium, and glutathione. We also found transcriptomic manifestations of increased cardiomyocyte polyploidy, such as the induction of gene modules related to open chromatin, e.g., "negative regulation of chromosome organization", "transcription" and "ribosome biogenesis". These findings suggest that ploidy-related epigenetic alterations acquired in the neonatal period permanently rewire gene regulatory networks and alter cardiomyocyte transcriptome. Here we provided first evidence indicating that NLI can be an important trigger of developmental programming of adult cardiovascular disease. The obtained results can help to develop preventive strategies for reducing the NLI-associated adverse effects of inflammation on the developing cardiovascular system.
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Affiliation(s)
| | - Andrey L Runov
- The D.I. Mendeleev All-Russian Institute for Metrology (VNIIM), Moskovsky ave 19, Saint Petersburg 190005, Russia
- Almazov Medical Research Centre, Akkuratova Street 2, Saint Petersburg 197341, Russia
| | | | - Maxim S Vonsky
- The D.I. Mendeleev All-Russian Institute for Metrology (VNIIM), Moskovsky ave 19, Saint Petersburg 190005, Russia
- Almazov Medical Research Centre, Akkuratova Street 2, Saint Petersburg 197341, Russia
| | - Artem U Elmuratov
- Medical Genetics Centre Genotek, Nastavnichesky Alley 17-1-15, Moscow 105120, Russia
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Bacova BS, Andelova K, Sykora M, Egan Benova T, Barancik M, Kurahara LH, Tribulova N. Does Myocardial Atrophy Represent Anti-Arrhythmic Phenotype? Biomedicines 2022; 10:2819. [PMID: 36359339 PMCID: PMC9687767 DOI: 10.3390/biomedicines10112819] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/31/2022] [Accepted: 11/02/2022] [Indexed: 11/30/2023] Open
Abstract
This review focuses on cardiac atrophy resulting from mechanical or metabolic unloading due to various conditions, describing some mechanisms and discussing possible strategies or interventions to prevent, attenuate or reverse myocardial atrophy. An improved awareness of these conditions and an increased focus on the identification of mechanisms and therapeutic targets may facilitate the development of the effective treatment or reversion for cardiac atrophy. It appears that a decrement in the left ventricular mass itself may be the central component in cardiac deconditioning, which avoids the occurrence of life-threatening arrhythmias. The depressed myocardial contractility of atrophied myocardium along with the upregulation of electrical coupling protein, connexin43, the maintenance of its topology, and enhanced PKCƐ signalling may be involved in the anti-arrhythmic phenotype. Meanwhile, persistent myocardial atrophy accompanied by oxidative stress and inflammation, as well as extracellular matrix fibrosis, may lead to severe cardiac dysfunction, and heart failure. Data in the literature suggest that the prevention of heart failure via the attenuation or reversion of myocardial atrophy is possible, although this requires further research.
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Affiliation(s)
| | - Katarina Andelova
- Centre of Experimental Medicine, Slovak Academy of Sciences, 84104 Bratislava, Slovakia
| | - Matus Sykora
- Centre of Experimental Medicine, Slovak Academy of Sciences, 84104 Bratislava, Slovakia
| | - Tamara Egan Benova
- Centre of Experimental Medicine, Slovak Academy of Sciences, 84104 Bratislava, Slovakia
| | - Miroslav Barancik
- Centre of Experimental Medicine, Slovak Academy of Sciences, 84104 Bratislava, Slovakia
| | - Lin Hai Kurahara
- Department of Cardiovascular Physiology, Faculty of Medicine, Kagawa University, Miki-cho 761-0793, Japan
| | - Narcis Tribulova
- Centre of Experimental Medicine, Slovak Academy of Sciences, 84104 Bratislava, Slovakia
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3
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Dadson K, Kovacevic V, Rengasamy P, Kim GHE, Boo S, Li RK, George I, Schulze PC, Hinz B, Sweeney G. Cellular, structural and functional cardiac remodelling following pressure overload and unloading. Int J Cardiol 2016; 216:32-42. [PMID: 27140334 DOI: 10.1016/j.ijcard.2016.03.240] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 03/25/2016] [Accepted: 03/27/2016] [Indexed: 01/18/2023]
Abstract
BACKGROUND The cardiac remodelling process in advanced heart failure due to pressure overload has not been clearly defined but likely involves mechanisms of cardiac fibrosis and cardiomyocyte hypertrophy. The aim of this study was to examine pressure overload (PO)-induced cardiac remodelling processes and their reversibility after unloading in both humans with heart failure and a mouse model of PO induced by aortic constriction. METHODS & RESULTS Speckle tracking echocardiography showed PO-induced cardiac dysfunction in mice was reversible after removal of aortic constriction to unload. Masson's Trichrome staining suggested that PO-induced myocardial fibrosis was reversible, however detailed analysis of 3-dimensional collagen architecture by scanning electron microscopy demonstrated that matrix remodelling was not completely normalised as a disorganised network of thin collagen fibres was evident. Analysis of human left ventricular biopsy samples from HF patients revealed increased presence of large collagen fibres which were greatly reduced in paired samples from the same individuals after unloading by left ventricular assist device implantation. Again, an extensive network of small collagen fibres was still clearly seen to closely surround cardiomyocytes after unloading. Other features of PO-induced remodelling including increased myofibroblast content, cardiomyocyte disarray and hypertrophy were largely reversed upon unloading in both humans and mouse model. Previous work in humans demonstrated that receptors for adiponectin, an important mediator of cardiac fibrosis and hypertrophy, decreased in heart failure patients and returned to normal after unloading. Here we provide novel data showing a similar trend for adiponectin receptor adaptor protein APPL1, but not APPL2 isoform. CONCLUSIONS LV unloading diminishes PO-induced cardiac remodelling and improves function. These findings add new insights into the cardiac remodelling process, and provide novel targets for future pharmacologic therapies.
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Affiliation(s)
- Keith Dadson
- Department of Biology, York University, Toronto, Canada
| | | | | | | | - Stellar Boo
- Laboratory of Tissue Repair and Regeneration, Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, Canada
| | - Ren-Ke Li
- Division of Cardiovascular Surgery and Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Isaac George
- Department of Internal Medicine I, Division of Cardiology, Friedrich Schiller University Jena, Jena, Germany; Division of Cardiology, Department of Medicine, Columbia University Medical Center, New York, USA
| | - P Christian Schulze
- Department of Internal Medicine I, Division of Cardiology, Friedrich Schiller University Jena, Jena, Germany; Division of Cardiology, Department of Medicine, Columbia University Medical Center, New York, USA
| | - Boris Hinz
- Laboratory of Tissue Repair and Regeneration, Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, Canada
| | - Gary Sweeney
- Department of Biology, York University, Toronto, Canada.
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Drews O, Taegtmeyer H. Targeting the ubiquitin-proteasome system in heart disease: the basis for new therapeutic strategies. Antioxid Redox Signal 2014; 21:2322-43. [PMID: 25133688 PMCID: PMC4241867 DOI: 10.1089/ars.2013.5823] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
SIGNIFICANCE Novel therapeutic strategies to treat heart failure are greatly needed. The ubiquitin-proteasome system (UPS) affects the structure and function of cardiac cells through targeted degradation of signaling and structural proteins. This review discusses both beneficial and detrimental consequences of modulating the UPS in the heart. RECENT ADVANCES Proteasome inhibitors were first used to test the role of the UPS in cardiac disease phenotypes, indicating therapeutic potential. In early cardiac remodeling and pathological hypertrophy with increased proteasome activities, proteasome inhibition prevented or restricted disease progression and contractile dysfunction. Conversely, enhancing proteasome activities by genetic manipulation, pharmacological intervention, or ischemic preconditioning also improved the outcome of cardiomyopathies and infarcted hearts with impaired cardiac and UPS function, which is, at least in part, caused by oxidative damage. CRITICAL ISSUES An understanding of the UPS status and the underlying mechanisms for its potential deregulation in cardiac disease is critical for targeted interventions. Several studies indicate that type and stage of cardiac disease influence the dynamics of UPS regulation in a nonlinear and multifactorial manner. Proteasome inhibitors targeting all proteasome complexes are associated with cardiotoxicity in humans. Furthermore, the type and dosage of proteasome inhibitor impact the pathogenesis in nonuniform ways. FUTURE DIRECTIONS Systematic analysis and targeting of individual UPS components with established and innovative tools will unravel and discriminate regulatory mechanisms that contribute to and protect against the progression of cardiac disease. Integrating this knowledge in drug design may reduce adverse effects on the heart as observed in patients treated with proteasome inhibitors against noncardiac diseases, especially cancer.
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Affiliation(s)
- Oliver Drews
- 1 Division of Cardiovascular Physiology, Institute of Physiology and Pathophysiology , Heidelberg University, Heidelberg, Germany
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5
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Dipchand AI, White M, Manlhiot C, Pollock-BarZiv S, Allain-Rooney T, West L, He Y, Touyz RM. Myocyte growth, repair, and oxidative stress following pediatric heart transplantation. Pediatr Transplant 2014; 18:764-70. [PMID: 25118092 DOI: 10.1111/petr.12337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/12/2014] [Indexed: 11/29/2022]
Abstract
Cardiac remodeling is associated with plasma biomarkers of fibrinogenesis, inflammation, and oxidative stress, and upregulation of mitogenic, pro-fibrotic, and apoptotic signaling pathways. Our primary objective was to evaluate biomarker and subcellular myocardial changes in pediatric heart transplant recipients. Fifty-two-week prospective, randomized (tacrolimus, Tac, vs. cyclosporine, CsA), open-label, parallel group study. Serial myocardial biopsies were probed for mitogenic and pro-inflammatory proteins. Plasma biomarkers of oxidative stress (F2α isoprostanes, nitrotyrosine), and inflammation and oxidation (hsCRP and cystatin-C) were measured. Nine of 11 randomized patients completed the study (four Tac, five CsA). Mean levels of F2α isoprostanes, hsCRP, and cystatin-C were maximal at Week 2. Peak activation of all MAP kinases in myocardial tissue was maximal at Week 10; no association was seen with rejection. Cardiac Bax/Bcl-2 levels (index of apoptosis) correlated negatively with F2α isoprostanes at Week 2 (r = -0.88) and with hsCRP at Week 52 (r = -0.67). At Week 52, hsCRP levels correlated positively with molecular indices of cardiac cell growth. We found evidence of systemic and myocardial oxidative damage and inflammation early posttransplant, which may be related to the remodeling process. Further study is needed to better understand the cardiac and systemic repair processes following pediatric heart transplantation.
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Affiliation(s)
- Anne I Dipchand
- Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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Myocardial Atrophy and Chronic Mechanical Unloading of the Failing Human Heart. J Am Coll Cardiol 2014; 64:1602-12. [DOI: 10.1016/j.jacc.2014.05.073] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 05/13/2014] [Indexed: 11/20/2022]
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7
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Zhu W, Zhang W, Shou W, Field LJ. P53 inhibition exacerbates late-stage anthracycline cardiotoxicity. Cardiovasc Res 2014; 103:81-9. [PMID: 24812279 DOI: 10.1093/cvr/cvu118] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
AIMS Doxorubicin (DOX) is an effective anti-cancer therapeutic, but is associated with both acute and late-stage cardiotoxicity. Children are particularly sensitive to DOX-induced heart failure. Here, the impact of p53 inhibition on acute vs. late-stage DOX cardiotoxicity was examined in a juvenile model. METHODS AND RESULTS Two-week-old MHC-CB7 mice (which express dominant-interfering p53 in cardiomyocytes) and their non-transgenic (NON-TXG) littermates received weekly DOX injections for 5 weeks (25 mg/kg cumulative dose). One week after the last DOX treatment (acute stage), MHC-CB7 mice exhibited improved cardiac function and lower levels of cardiomyocyte apoptosis when compared with the NON-TXG mice. Surprisingly, by 13 weeks following the last DOX treatment (late stage), MHC-CB7 exhibited a progressive decrease in cardiac function and higher rates of cardiomyocyte apoptosis when compared with NON-TXG mice. p53 inhibition blocked transient DOX-induced STAT3 activation in MHC-CB7 mice, which was associated with enhanced induction of the DNA repair proteins Ku70 and Ku80. Mice with cardiomyocyte-restricted deletion of STAT3 exhibited worse cardiac function, higher levels of cardiomyocyte apoptosis, and a greater induction of Ku70 and Ku80 in response to DOX treatment during the acute stage when compared with control animals. CONCLUSION These data support a model wherein a p53-dependent cardioprotective pathway, mediated via STAT3 activation, mitigates DOX-induced myocardial stress during drug delivery. Furthermore, these data suggest an explanation as to how p53 inhibition can result in cardioprotection during drug treatment and, paradoxically, enhanced cardiotoxicity long after the cessation of drug treatment.
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Affiliation(s)
- Wuqiang Zhu
- The Riley Heart Research Center, Wells Center for Pediatric Research, 1044 West Walnut Street; R4 Building Room W376, Indianapolis, IN 46202-5225, USA
| | - Wenjun Zhang
- The Riley Heart Research Center, Wells Center for Pediatric Research, 1044 West Walnut Street; R4 Building Room W376, Indianapolis, IN 46202-5225, USA
| | - Weinian Shou
- The Riley Heart Research Center, Wells Center for Pediatric Research, 1044 West Walnut Street; R4 Building Room W376, Indianapolis, IN 46202-5225, USA
| | - Loren J Field
- The Riley Heart Research Center, Wells Center for Pediatric Research, 1044 West Walnut Street; R4 Building Room W376, Indianapolis, IN 46202-5225, USA The Krannert Institute of Cardiology, Indiana University School of Medicine, 1044 West Walnut Street, Indianapolis, IN 46202, USA
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Baskin KK, Rodriguez MR, Kansara S, Chen W, Carranza S, Frazier OH, Glass DJ, Taegtmeyer H. MAFbx/Atrogin-1 is required for atrophic remodeling of the unloaded heart. J Mol Cell Cardiol 2014; 72:168-76. [PMID: 24650875 DOI: 10.1016/j.yjmcc.2014.03.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 03/06/2014] [Accepted: 03/07/2014] [Indexed: 12/17/2022]
Abstract
BACKGROUND Mechanical unloading of the failing human heart induces profound cardiac changes resulting in the reversal of a distorted structure and function. In this process, cardiomyocytes break down unneeded proteins and replace those with new ones. The specificity of protein degradation via the ubiquitin proteasome system is regulated by ubiquitin ligases. Over-expressing the ubiquitin ligase MAFbx/Atrogin-1 in the heart inhibits the development of cardiac hypertrophy, but the role of MAFbx/Atrogin-1 in the unloaded heart is not known. METHODS AND RESULTS Mechanical unloading, by heterotopic transplantation, decreased heart weight and cardiomyocyte cross-sectional area in wild type mouse hearts. Unexpectedly, MAFbx/Atrogin-1(-/-) hearts hypertrophied after transplantation (n=8-10). Proteasome activity and markers of autophagy were increased to the same extent in WT and MAFbx/Atrogin-1(-/-) hearts after transplantation (unloading). Calcineurin, a regulator of cardiac hypertrophy, was only upregulated in MAFbx/Atrogin-1(-/-) transplanted hearts, while the mTOR pathway was similarly activated in unloaded WT and MAFbx/Atrogin-1(-/-) hearts. MAFbx/Atrogin-1(-/-) cardiomyocytes exhibited increased calcineurin protein expression, NFAT transcriptional activity, and protein synthesis rates, while inhibition of calcineurin normalized NFAT activity and protein synthesis. Lastly, mechanical unloading of failing human hearts with a left ventricular assist device (n=18) also increased MAFbx/Atrogin-1 protein levels and expression of NFAT regulated genes. CONCLUSIONS MAFbx/Atrogin-1 is required for atrophic remodeling of the heart. During unloading, MAFbx/Atrogin-1 represses calcineurin-induced cardiac hypertrophy. Therefore, MAFbx/Atrogin-1 not only regulates protein degradation, but also reduces protein synthesis, exerting a dual role in regulating cardiac mass.
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Affiliation(s)
- Kedryn K Baskin
- Department of Internal Medicine, Division of Cardiology, The University of Texas Health Science Center, Houston, TX, USA
| | - Meredith R Rodriguez
- Department of Internal Medicine, Division of Cardiology, The University of Texas Health Science Center, Houston, TX, USA
| | - Seema Kansara
- Department of Internal Medicine, Division of Cardiology, The University of Texas Health Science Center, Houston, TX, USA
| | - Wenhao Chen
- Department of Endocrinology, Baylor College of Medicine, Houston, TX, USA
| | | | | | - David J Glass
- Department of Muscle Diseases, Novartis Institute for Biomedical Research, Cambridge, MA, USA
| | - Heinrich Taegtmeyer
- Department of Internal Medicine, Division of Cardiology, The University of Texas Health Science Center, Houston, TX, USA; Texas Heart Institute, Houston, TX, USA.
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Schluesener JK, Schluesener H. Plant polyphenols in the treatment of age-associated diseases: revealing the pleiotropic effects of icariin by network analysis. Mol Nutr Food Res 2013; 58:49-60. [PMID: 24311544 DOI: 10.1002/mnfr.201300409] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 10/18/2013] [Accepted: 10/30/2013] [Indexed: 12/15/2022]
Abstract
Polyphenols are a broad class of compounds. Some are ingested in substantial quantities from nutritional sources, more are produced by medicinal plants, and some of them are taken as drugs. It is becoming clear, that a single polyphenol is impacting several cellular pathways. Thus, a network approach is becoming feasible, describing the interaction of a single polyphenol with cellular networks. Here we have selected icariin to draw a prototypic network of icariin activities. Icariin appears to be a promising drug to treat major age-related diseases, like neurodegeneration, memory and depressive disorders, chronic inflammation, diabetes, and osteoporosis. It interacts with several relevant pathways, like PDE, TGF-ß, MAPK, PPAR, NOS, IGF, Sirtuin, and others. Such networks will be useful to future comparative studies of complex effects of polyphenols.
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Affiliation(s)
- Jan Kevin Schluesener
- Division of Immunopathology of the Nervous System, Department of Neuropathology, Institute of Pathology and Neuropathology, University of Tuebingen, Tuebingen, Germany
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10
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Cardiac signaling molecules and plasma biomarkers after cardiac transplantation: Impact of tacrolimus versus cyclosporine. J Heart Lung Transplant 2013; 32:1222-32. [DOI: 10.1016/j.healun.2013.09.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 08/01/2013] [Accepted: 09/17/2013] [Indexed: 02/07/2023] Open
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Zaglia T, Milan G, Franzoso M, Bertaggia E, Pianca N, Piasentini E, Voltarelli VA, Chiavegato D, Brum PC, Glass DJ, Schiaffino S, Sandri M, Mongillo M. Cardiac sympathetic neurons provide trophic signal to the heart via β2-adrenoceptor-dependent regulation of proteolysis. Cardiovasc Res 2012; 97:240-50. [DOI: 10.1093/cvr/cvs320] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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12
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Usui S, Maejima Y, Pain J, Hong C, Cho J, Park JY, Zablocki D, Tian B, Glass DJ, Sadoshima J. Endogenous muscle atrophy F-box mediates pressure overload-induced cardiac hypertrophy through regulation of nuclear factor-kappaB. Circ Res 2011; 109:161-71. [PMID: 21617130 DOI: 10.1161/circresaha.110.238717] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
RATIONALE Overexpression of muscle atrophy F-box (MAFbx/atrogin-1), an E3 ubiquitin ligase, induces proteasomal degradation in cardiomyocytes. The role of endogenous MAFbx in regulating cardiac hypertrophy and failure remains unclear. OBJECTIVE We investigated the role of MAFbx in regulating cardiac hypertrophy and function in response to pressure overload. Transverse aortic constriction (TAC) was applied to MAFbx knockout (KO) and wild-type (WT) mice. METHODS AND RESULTS Expression of MAFbx in WT mice was significantly increased by TAC. TAC-induced increases in cardiac hypertrophy were significantly smaller in MAFbx KO than in WT mice. There was significantly less lung congestion and interstitial fibrosis in MAFbx KO than in WT mice. MAFbx KO also inhibited β-adrenergic cardiac hypertrophy. DNA microarray analysis revealed that activation of genes associated with the transcription factor binding site for the nuclear factor-κB family were inhibited in MAFbx KO mice compared with WT mice after TAC. Although the levels of IκB-α were significantly decreased after TAC in WT mice, they were increased in MAFbx KO mice. MAFbx regulates ubiquitination and proteasomal degradation of IκB-α in cardiomyocytes. In primary cultured rat cardiomyocytes, phenylephrine-induced activation of nuclear factor-κB and hypertrophy were significantly suppressed by MAFbx knockdown but were partially rescued by overexpression of nuclear factor-κB p65. CONCLUSIONS MAFbx plays an essential role in mediating cardiac hypertrophy in response to pressure overload. Downregulation of MAFbx inhibits cardiac hypertrophy in part through stabilization of IκB-α and inactivation of nuclear factor-κB. Taken together, inhibition of MAFbx attenuates pathological hypertrophy, thereby protecting the heart from progression into heart failure.
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Affiliation(s)
- Soichiro Usui
- Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, UMDNJ, New Jersey Medical School, Newark, NJ, USA
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Ambardekar AV, Buttrick PM. Reverse remodeling with left ventricular assist devices: a review of clinical, cellular, and molecular effects. Circ Heart Fail 2011; 4:224-33. [PMID: 21406678 DOI: 10.1161/circheartfailure.110.959684] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Amrut V Ambardekar
- Division of Cardiology, University of Colorado Denver, Aurora, CO 80045, USA.
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Ambardekar AV, Walker JS, Walker LA, Cleveland JC, Lowes BD, Buttrick PM. Incomplete recovery of myocyte contractile function despite improvement of myocardial architecture with left ventricular assist device support. Circ Heart Fail 2011; 4:425-32. [PMID: 21540356 DOI: 10.1161/circheartfailure.111.961326] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Unloading a failing heart with a left ventricular assist device (LVAD) can improve ejection fraction (EF) and LV size; however, recovery with LVAD explantation is rare. We hypothesized that evaluation of myocyte contractility and biochemistry at the sarcomere level before and after LVAD may explain organ-level changes. METHODS AND RESULTS Paired LV tissue samples were frozen from 8 patients with nonischemic cardiomyopathy at LVAD implantation (before LVAD) and before cardiac transplantation (after LVAD). These were compared with 8 nonfailing hearts. Isolated skinned myocytes were purified and attached to a force transducer, and dimensions, maximum calcium-saturated force, calcium sensitivity, and myofilament cooperativity were assessed. Relative isoform abundance and phosphorylation levels of sarcomeric contractile proteins were measured. With LVAD support, the unloaded EF improved (10.0±1.0% to 25.6±11.0%, P=0.007), LV size decreased (LV internal dimension at end diastole, 7.6±1.2 to 4.9±1.4 cm; P<0.001), and myocyte dimensions decreased (cross-sectional area, 1247±346 to 638±254 μm(2); P=0.001). Maximum calcium-saturated force improved after LVAD (3.6±0.9 to 7.3±1.8 mN/mm(2), P<0.001) implantation but was still lower than in nonfailing hearts (7.3±1.8 versus 17.6±1.8 mN/mm(2), P<0.001). An increase in troponin I (TnI) phosphorylation after LVAD implantation was noted, but protein kinase C phosphorylation of TnI decreased. Biochemical changes of other sarcomeric proteins were not observed after LVAD. CONCLUSIONS There is significant improvement in LV and myocyte size with LVAD, but there is only partial recovery of EF and myocyte contractility. LVAD support was associated only with biochemical changes in TnI, suggesting that alternate mechanisms might contribute to contractile changes after LVAD and that additional interventions may be needed to alter biochemical remodeling of the sarcomere to further enhance myofilament and organ-level recovery.
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Affiliation(s)
- Amrut V Ambardekar
- Division of Cardiology, University of Colorado Denver, Aurora, CO 80045, USA.
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Felkin LE, Lara-Pezzi EA, Hall JL, Birks EJ, Barton PJR. Reverse Remodelling and Recovery from Heart Failure Are Associated with Complex Patterns of Gene Expression. J Cardiovasc Transl Res 2011; 4:321-31. [DOI: 10.1007/s12265-011-9267-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 02/15/2011] [Indexed: 11/30/2022]
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Baskin KK, Taegtmeyer H. Taking pressure off the heart: the ins and outs of atrophic remodelling. Cardiovasc Res 2011; 90:243-50. [PMID: 21354996 DOI: 10.1093/cvr/cvr060] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Our work on atrophic remodelling of the heart has led us to appreciate the simple principles in biology: (i) the dynamic nature of intracellular protein turnover, (ii) the return to the foetal gene programme when the heart remodels, and (iii) the adaptive changes of cardiac metabolism. Although the molecular mechanisms of cardiac hypertrophy are many, much less is known regarding the molecular mechanisms of cardiac atrophy. We state the case that knowing more about mechanisms of atrophic remodelling may provide insights into cellular consequences of metabolic and haemodynamic unloading of the stressed heart. Overall we strive to find an answer to the question: 'What makes the failing heart shrink and become stronger?' We speculate that signals arising from intermediary metabolism of energy-providing substrates are likely candidates.
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Affiliation(s)
- Kedryn K Baskin
- Department of Internal Medicine, Division of Cardiology, The University of Texas School of Medicine at Houston, 6431 Fannin, MSB 1.246, Houston, TX 77030, USA
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Clenbuterol Induces Cardiac Myocyte Hypertrophy via Paracrine Signalling and Fibroblast-derived IGF-1. J Cardiovasc Transl Res 2010; 3:688-95. [DOI: 10.1007/s12265-010-9199-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Accepted: 05/27/2010] [Indexed: 01/08/2023]
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Abstract
The ubiquitin-proteasome system (UPS) is a major proteolytic system that regulates the degradation of intracellular proteins in the heart. The UPS regulates the turnover of misfolded and damaged proteins, in addition to numerous cellular processes, by affecting the stability of short-lived proteins such as transcription factors and cell signaling pathways. The UPS is tightly regulated by the specificity of ubiquitin ligases that recognize specific substrates and direct the addition of ubiquitin, targeting the substrates for degradation by the 26S proteasome. An increasing number of cardiac ubiquitin ligases have been identified, and the number of substrates each one is known to recognize also has increased, expanding their roles. Although mainly cardioprotective roles have been attributed to ubiquitin ligases, new studies have identified exceptions to this rule. This review discusses the mechanisms of cardiac ubiquitin ligases and identifies their role in common cardiac diseases including cardiac hypertrophy, cardiac atrophy, ischemic heart disease, and diabetic cardiomyopathy.
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Koike M, Kojima H, Fujimiya M, Matsubayashi K, Aimi Y, Kimura H, Asai T. Transfer of bone marrow progenitors prevents coronary insufficiency and systolic dysfunction in the mechanical unloaded heart in mice. J Surg Res 2010; 171:47-57. [PMID: 20451917 DOI: 10.1016/j.jss.2010.01.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 01/21/2010] [Accepted: 01/25/2010] [Indexed: 12/19/2022]
Abstract
BACKGROUND Left ventricular-assist device (LVAD) can lead to improvement of cardiac performance in a subset of patients, but chronic mechanical unloading in this fashion may result in left ventricular (LV)-atrophy and impaired functional recovery. Here, we evaluate the efficacy of transferring bone-marrow KSL cells (Lin-/c-kit+/Sca1+), a fraction containing endothelial progenitor cells, for preventing LV-atrophy and malfunction in a mouse model of mechanical unloading of the heart. MATERIALS AND METHODS Recipients of an isogenic heart transplant received intramyocardial isogenic KSL cells or PBS in three different locations of the left ventricle (LV). Coronary blood flow and LV systolic function were evaluated by echocardiography, and morphologic changes were analyzed on d 7 and 56. RESULTS PBS-treated mice showed severe systolic dysfunction and large thrombi in LV at both time points. In contrast, KSL cell transfer markedly reduced systolic dysfunction and thrombus size. Furthermore, in comparison with PBS control, KSL recipients had increased coronary blood flow (3-fold, P < 0.01) accompanied by increased LV capillary density and muscle mass. CONCLUSIONS These results indicate that intramyocardial transfer of bone marrow KSL cells significantly protects against coronary insufficiency and systolic dysfunction in the chronic LV-unloading heart, suggesting that this approach may have clinical potential as a combination therapy with LVAD.
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Affiliation(s)
- Masato Koike
- Department of Surgery, Shiga University of Medical Science, Otsu, Shiga, Japan
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Abstract
The mammalian target of rapamycin (mTOR) signaling network regulates cell growth, proliferation and cell survival. Deregulated activation of this pathway is a common event in diverse human diseases such as cancers, cardiac hypertrophy, vascular restenosis and nephrotic hypertrophy. Although mTOR inhibitor, rapamycin, has been widely used to inhibit the aberrant signaling due to mTOR activation that plays a major role in hyperproliferative diseases, in some cases rapamycin does not attenuate the cell proliferation and survival. Thus, we studied the mechanism(s) by which cells may confer resistance to rapamycin. Our data show that in a variety of cell types the mTOR inhibitor rapamycin activates extracellularly regulated kinases (Erk1/2) signaling. Rapamycin-mediated activation of the Erk1/2 signaling requires (a) the epidermal growth factor receptor (EGFR), (b) its tyrosine kinase activity and (c) intact autophosphorylation sites on the receptor. Rapamycin treatment increases tyrosine phosphorylation of EGFR without the addition of growth factor and this transactivation of receptor involves activation of c-Src. We also show that rapamycin treatment triggers activation of cell survival signaling pathway by activating the prosurvival kinases Erk1/2 and p90RSK. These studies provide a novel paradigm by which cells escape the apoptotic actions of rapamycin and its derivatives that inhibit the mTOR pathway.
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Zhu W, Soonpaa MH, Chen H, Shen W, Payne RM, Liechty EA, Caldwell RL, Shou W, Field LJ. Acute doxorubicin cardiotoxicity is associated with p53-induced inhibition of the mammalian target of rapamycin pathway. Circulation 2008; 119:99-106. [PMID: 19103993 DOI: 10.1161/circulationaha.108.799700] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Doxorubicin is used to treat childhood and adult cancer. Doxorubicin treatment is associated with both acute and chronic cardiotoxicity. The cardiotoxic effects of doxorubicin are cumulative, which limits its chemotherapeutic dose. Free radical generation and p53-dependent apoptosis are thought to contribute to doxorubicin-induced cardiotoxicity. METHODS AND RESULTS Adult transgenic (MHC-CB7) mice expressing cardiomyocyte-restricted dominant-interfering p53 and their nontransgenic littermates were treated with doxorubicin (20 mg/kg cumulative dose). Nontransgenic mice exhibited reduced left ventricular systolic function (predoxorubicin fractional shortening [FS] 61+/-2%, postdoxorubicin FS 45+/-2%, mean+/-SEM, P<0.008), reduced cardiac mass, and high levels of cardiomyocyte apoptosis 7 days after the initiation of doxorubicin treatment. In contrast, doxorubicin-treated MHC-CB7 mice exhibited normal left ventricular systolic function (predoxorubicin FS 63+/-2%, postdoxorubicin FS 60+/-2%, P>0.008), normal cardiac mass, and low levels of cardiomyocyte apoptosis. Western blot analyses indicated that mTOR (mammalian target of rapamycin) signaling was inhibited in doxorubicin-treated nontransgenic mice but not in doxorubicin-treated MHC-CB7 mice. Accordingly, transgenic mice with cardiomyocyte-restricted, constitutively active mTOR expression (MHC-mTORca) were studied. Left ventricular systolic function (predoxorubicin FS 64+/-2%, postdoxorubicin FS 60+/-3%, P>0.008) and cardiac mass were normal in doxorubicin-treated MHC-mTORca mice, despite levels of cardiomyocyte apoptosis similar to those seen in doxorubicin-treated nontransgenic mice. CONCLUSIONS These data suggest that doxorubicin treatment induces acute cardiac dysfunction and reduces cardiac mass via p53-dependent inhibition of mTOR signaling and that loss of myocardial mass, and not cardiomyocyte apoptosis, is the major contributor to acute doxorubicin cardiotoxicity.
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Affiliation(s)
- Wuqiang Zhu
- Riley Heart Research Center, Herman B Wells Center for Pediatric Research, Indianapolis, IN 46202-5225, USA
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Mearini G, Schlossarek S, Willis MS, Carrier L. The ubiquitin–proteasome system in cardiac dysfunction. Biochim Biophys Acta Mol Basis Dis 2008; 1782:749-63. [DOI: 10.1016/j.bbadis.2008.06.009] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 06/12/2008] [Accepted: 06/18/2008] [Indexed: 12/31/2022]
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Schwoerer AP, Neuber C, Schmechel A, Melnychenko I, Mearini G, Boknik P, Kirchhefer U, Schmitz W, Ehmke H, Eschenhagen T, El-Armouche A. Mechanical unloading of the rat heart involves marked changes in the protein kinase–phosphatase balance. J Mol Cell Cardiol 2008; 45:846-52. [DOI: 10.1016/j.yjmcc.2008.09.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 09/08/2008] [Accepted: 09/08/2008] [Indexed: 02/06/2023]
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24
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Schwoerer AP, Melnychenko I, Goltz D, Hedinger N, Broichhausen I, El-Armouche A, Eschenhagen T, Volk T, Ehmke H. Unloaded rat hearts in vivo express a hypertrophic phenotype of cardiac repolarization. J Mol Cell Cardiol 2008; 45:633-41. [DOI: 10.1016/j.yjmcc.2008.02.271] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Revised: 02/11/2008] [Accepted: 02/12/2008] [Indexed: 11/25/2022]
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Kassiotis C, Rajabi M, Taegtmeyer H. Metabolic reserve of the heart: the forgotten link between contraction and coronary flow. Prog Cardiovasc Dis 2008; 51:74-88. [PMID: 18634919 DOI: 10.1016/j.pcad.2007.11.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Myocardial energy substrate metabolism entails a complex system of enzyme catalyzed reactions, in which the heart efficiently converts chemical to mechanical energy. The system is highly regulated and responsive to changes in workload as well as in substrate and hormone supply to the heart. Akin to the terms "contractile reserve" and "coronary flow reserve" we propose the term "metabolic reserve" to reflect the heart's capacity to respond to increases in workload. The heart's metabolic response to inotropic stimulation involves the ability to increase oxidative metabolism over a wide range, by activating the oxidation of glycogen and carbohydrate substrates. Here we review the known biochemical mechanisms responsible for those changes. Specifically, we explore the notion that disturbances in the metabolic reserve result in contractile dysfunction of the stressed heart.
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Affiliation(s)
- Christos Kassiotis
- Department of Internal Medicine, Division of Cardiology, The University of Texas Houston Medical School, Houston, TX 77030, USA
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Abstract
PURPOSE OF REVIEW There is considerable increase in the use of left ventricular assist devices for the treatment of severe heart failure. Traditionally viewed as a bridge to transplantation and more recently as a destination therapy, left ventricular assist device support is now recognized to offer potential for myocardial recovery through reverse remodeling, a potential that is further enhanced by combination with pharmacologic therapy. In this study, we examine the molecular changes associated with left ventricular assist device support and how these may contribute to the recovery process. RECENT FINDINGS Studies in both patients and experimental models have demonstrated that improved function is associated with alterations in several key pathways including cell survival, cytokine signaling, calcium handling, adrenergic receptor signaling, cytoskeletal and contractile proteins, energy metabolism, extracellular matrix, and endothelial and microvascular functions. Moreover, the unique research opportunities offered by left ventricular assist device analysis are beginning to distinguish changes associated with recovery from those of mechanical unloading alone and identify potential predictors and novel therapeutic targets capable of enhancing myocardial repair. SUMMARY Significant progress has been made toward revealing molecular changes associated with myocardial recovery from heart failure. These studies also offer new insight into the pathogenesis of heart failure and point to novel therapeutic strategies.
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Normalization of Ejection Fraction and Resolution of Symptoms in Chronic Severe Heart Failure is Possible With Modern Medical Therapy: Clinical Observations in 11 Patients. Am J Ther 2008; 15:206-13. [DOI: 10.1097/mjt.0b013e3181728a1d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Otis JS, Ashikhmin YI, Brown L, Guidot DM. Effect of HIV-1-related protein expression on cardiac and skeletal muscles from transgenic rats. AIDS Res Ther 2008; 5:8. [PMID: 18439274 PMCID: PMC2365956 DOI: 10.1186/1742-6405-5-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Accepted: 04/25/2008] [Indexed: 12/19/2022] Open
Abstract
Background Human immunodeficiency virus type 1 (HIV-1) infection and the consequent acquired immunodeficiency syndrome (AIDS) has protean manifestations, including muscle wasting and cardiomyopathy, which contribute to its high morbidity. The pathogenesis of these myopathies remains partially understood, and may include nutritional deficiencies, biochemical abnormalities, inflammation, and other mechanisms due to viral infection and replication. Growing evidence has suggested that HIV-1-related proteins expressed by the host in response to viral infection, including Tat and gp120, may also be involved in the pathophysiology of AIDS, particularly in cells or tissues that are not directly infected with HIV-1. To explore the potentially independent effects of HIV-1-related proteins on heart and skeletal muscles, we used a transgenic rat model that expresses several HIV-1-related proteins (e.g., Tat, gp120, and Nef). Outcome measures included basic heart and skeletal muscle morphology, glutathione metabolism and oxidative stress, and gene expressions of atrogin-1, muscle ring finger protein-1 (MuRF-1) and Transforming Growth Factor-β1 (TGFβ1), three factors associated with muscle catabolism. Results Consistent with HIV-1 associated myopathies in humans, HIV-1 transgenic rats had increased relative heart masses, decreased relative masses of soleus, plantaris and gastrocnemius muscles, and decreased total and myosin heavy chain type-specific plantaris muscle fiber areas. In both tissues, the levels of cystine (Cyss), the oxidized form of the anti-oxidant cysteine (Cys), and Cyss:Cys ratios were significantly elevated, and cardiac tissue from HIV-1 transgenic rats had altered glutathione metabolism, all reflective of significant oxidative stress. In HIV-1 transgenic rat hearts, MuRF-1 gene expression was increased. Further, HIV-1-related protein expression also increased atrogin-1 (~14- and ~3-fold) and TGFβ1 (~5-fold and ~3-fold) in heart and plantaris muscle tissues, respectively. Conclusion We provide compelling experimental evidence that HIV-1-related proteins can lead to significant cardiac and skeletal muscle complications independently of viral infection or replication. Our data support the concept that HIV-1-related proteins are not merely disease markers, but rather have significant biological activity that may lead to increased oxidative stress, the stimulation of redox-sensitive pathways, and altered muscle morphologies. If correct, this pathophysiological scheme suggests that the use of dietary thiol supplements could reduce skeletal and cardiac muscle dysfunction in HIV-1-infected individuals.
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Mikaelian I, Coluccio D, Morgan KT, Johnson T, Ryan AL, Rasmussen E, Nicklaus R, Kanwal C, Hilton H, Frank K, Fritzky L, Wheeldon EB. Temporal Gene Expression Profiling Indicates Early Up-regulation of Interleukin-6 in Isoproterenol-induced Myocardial Necrosis in Rat. Toxicol Pathol 2008; 36:256-64. [DOI: 10.1177/0192623307312696] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Gene expression was evaluated in the myocardium of male Wistar rats after a single subcutaneous administration of 0.5 mg of isoproterenol, a β-adrenergic agonist that causes acute tachycardia with subsequent myocardial necrosis. Histology of the heart, clinical chemistry, and hematology were evaluated at 9 time points (0.5 hours to 14 days postinjection). Myocardial gene expression was evaluated at 4 time points (1 hour to 3 days). Contraction bands and loss of cross-striation were identified on phosphotungstic acid-hematoxylin-stained sections 0.5 hours postdosing. Plasma troponin I elevation was detected at 0.5 hours, peaked at 3 hours, and returned to baseline values at 3 days postdosing. Interleukin 6 (Il6) expression spiked at 1 to 3 hours and was followed by a short-lived, time-dependent dysregulation of its downstream targets. Concurrently and consistent with the kinetics of the histologic findings, many pathways indicative of necrosis/apoptosis (p38 mitogen-activated protein kinase [MAPK] signaling, NF-κB signaling) and adaptation to hypertension (PPAR signaling) were overrepresented at 3 hours. The 1-day and 3-day time points indicated an adaptive response, with down-regulation of the fatty acid metabolism pathway, up-regulation of the fetal gene program, and superimposed inflammation and repair at 3 days. These results suggest early involvement of Il6 in isoproterenol-induced myocardial necrosis and emphasize the value of early time points in transcriptomic studies.
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Affiliation(s)
- Igor Mikaelian
- Hoffmann-La Roche Inc., Non-Clinical Drug Safety, Nutley, New Jersey, USA and
| | - Denise Coluccio
- Hoffmann-La Roche Inc., Non-Clinical Drug Safety, Nutley, New Jersey, USA and
| | | | - Teona Johnson
- Hoffmann-La Roche Inc., Non-Clinical Drug Safety, Nutley, New Jersey, USA and
| | - Amber L. Ryan
- Hoffmann-La Roche Inc., Non-Clinical Drug Safety, Nutley, New Jersey, USA and
| | - Erik Rasmussen
- Hoffmann-La Roche Inc., Non-Clinical Drug Safety, Nutley, New Jersey, USA and
| | - Rosemary Nicklaus
- Hoffmann-La Roche Inc., Non-Clinical Drug Safety, Nutley, New Jersey, USA and
| | - Charu Kanwal
- Hoffmann-La Roche Inc., Non-Clinical Drug Safety, Nutley, New Jersey, USA and
| | - Holly Hilton
- Hoffmann-La Roche Inc., Non-Clinical Drug Safety, Nutley, New Jersey, USA and
| | - Karl Frank
- Hoffmann-La Roche Inc., Non-Clinical Drug Safety, Nutley, New Jersey, USA and
| | - Luke Fritzky
- Hoffmann-La Roche Inc., Non-Clinical Drug Safety, Nutley, New Jersey, USA and
| | - Eric B. Wheeldon
- Hoffmann-La Roche Inc., Non-Clinical Drug Safety, Nutley, New Jersey, USA and
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Rajabi M, Kassiotis C, Razeghi P, Taegtmeyer H. Return to the fetal gene program protects the stressed heart: a strong hypothesis. Heart Fail Rev 2007; 12:331-43. [PMID: 17516164 DOI: 10.1007/s10741-007-9034-1] [Citation(s) in RCA: 318] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A common feature of the hemodynamically or metabolically stressed heart is the return to a pattern of fetal metabolism. A hallmark of fetal metabolism is the predominance of carbohydrates as substrates for energy provision in a relatively hypoxic environment. When the normal heart is exposed to an oxygen rich environment after birth, energy substrate metabolism is rapidly switched to oxidation of fatty acids. This switch goes along with the expression of "adult" isoforms of metabolic enzymes and other proteins. However, the heart retains the ability to return to the "fetal" gene program. Specifically, the fetal gene program is predominant in a variety of pathophysiologic conditions including hypoxia, ischemia, hypertrophy, and atrophy. A common feature of all of these conditions is extensive remodeling, a decrease in the rate of aerobic metabolism in the cardiomyocyte, and an increase in cardiac efficiency. The adaptation is associated with a whole program of cell survival under stress. The adaptive mechanisms are prominently developed in hibernating myocardium, but they are also a feature of the failing heart muscle. We propose that in failing heart muscle at a certain point the fetal gene program is no longer sufficient to support cardiac structure and function. The exact mechanisms underlying the transition from adaptation to cardiomyocyte dysfunction are still not completely understood.
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Affiliation(s)
- Mitra Rajabi
- Department of Internal Medicine, Division of Cardiology, University of Texas-Houston Medical School, 6431 Fannin, Houston, TX 77030, USA
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31
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Razeghi P, Wang ME, Youker KA, Golfman L, Stepkowski S, Taegtmeyer H. Lack of NF-kappaB1 (p105/p50) attenuates unloading-induced downregulation of PPARalpha and PPARalpha-regulated gene expression in rodent heart. Cardiovasc Res 2007; 74:133-9. [PMID: 17276423 PMCID: PMC2034318 DOI: 10.1016/j.cardiores.2006.12.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Revised: 12/19/2006] [Accepted: 12/22/2006] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVE Unloading of the rodent heart activates the fetal gene program, decreases peroxisome proliferator-activated receptor alpha (PPARalpha) and PPARalpha-regulated gene expression (MCAD), and induces cardiomyocyte atrophy. NF-kappaB regulates the fetal gene program and PPARalpha-regulated gene expression during cardiac hypertrophy and induces atrophy in skeletal muscle. Our objective was to test the hypothesis that NF-kappaB is the regulator for activation of the fetal gene program, for downregulation of PPARalpha and PPARalpha-regulated gene expression, and for cardiomyocyte atrophy in the heart subjected to mechanical unloading. METHODS Activation of the inhibitory kappa B kinase beta (IKKbeta)/NF-kappaB pathways were measured in the heterotopically transplanted rat heart using Western blotting of total and phospho-IKKbeta and using transcription factor ELISA's for the five members of the NF-kappaB family (p65 (Rel A), p105/p50, c-Rel, RelB, and p100/p52). In loss of function experiments, we transplanted hearts of p105/p50 knockout mice into wildtype mice and compared changes in gene expression and cardiomyocyte size with wildtype hearts transplanted into wildtype mice. RESULTS Total and phospho-IKKbeta levels significantly increased in the transplanted heart seven days after surgery. The activation of IKKbeta was paralleled by increased DNA binding activity of p65 and p105/p50. Mechanical unloading induced myosin heavy chain beta expression and decreased cardiomyocyte size in hearts of both wildtype and p105/p050 knockout animals. In contrast, the downregulation of PPARalpha and MCAD was significantly attenuated or prevented in the hearts of p105/p50 knockout mice. CONCLUSIONS The IKKbeta/p65/p50 pathway is activated in the unloaded rodent heart and a likely regulator for the downregulation of PPARalpha and PPARalpha-regulated gene expression.
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Affiliation(s)
- Peter Razeghi
- Division of Cardiology, University of Texas Houston-Medical School, Houston, Texas
| | - Mou-Er Wang
- Division of Organ Transplantation, University of Texas Houston-Medical School, Houston, Texas
| | - Keith A. Youker
- Division of Surgery, Baylor College of Medicine, Houston, Texas
| | - Leonard Golfman
- Division of Cardiothoracic and Vascular Surgery, University of Texas Houston-Medical School, Houston, Texas
| | - Stanislaw Stepkowski
- Division of Organ Transplantation, University of Texas Houston-Medical School, Houston, Texas
| | - Heinrich Taegtmeyer
- Division of Cardiology, University of Texas Houston-Medical School, Houston, Texas
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Koehn FE. Therapeutic potential of natural product signal transduction agents. Curr Opin Biotechnol 2006; 17:631-7. [PMID: 17049224 DOI: 10.1016/j.copbio.2006.09.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Revised: 08/20/2006] [Accepted: 09/29/2006] [Indexed: 01/22/2023]
Abstract
Modern drug discovery embraces a strategy of targeting cellular signal transduction pathways as a means of finding new therapeutic agents. Historically, natural products derived from microorganisms have played an important role as drug leads and clinical candidates under this paradigm. The future drug potential of natural products as signal transduction agents looks promising, as illustrated by two key examples. First, substantial advances have been made in the development of inhibitors based on immunophilin ligand polyketides, which target the TOR-mediated pathways and can modulate processes including cell proliferation and cell-cycle arrest. Second, the discovery of natural product inhibitors of the ubiquitin-proteasome proteolytic signal transduction pathway represents an emerging field. Given these examples, together with the diversity of as yet undiscovered agents, natural product signal transduction agents offer great potential for future drug discovery efforts.
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Affiliation(s)
- Frank E Koehn
- Natural Products Discovery, Chemical and Screening Sciences, Wyeth Research, 401 North Middletown Road, Pearl River, NY 10965, USA.
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Razeghi P, Taegtmeyer H. Hypertrophy and Atrophy of the Heart: The Other Side of Remodeling. Ann N Y Acad Sci 2006; 1080:110-9. [PMID: 17132779 DOI: 10.1196/annals.1380.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The size of a cardiomyocyte is determined by relative rates of protein synthesis and degradation. Signaling pathways regulating myocardial protein synthesis have been extensively investigated, not the least because in patients hypertrophy increases cardiovascular morbidity and mortality. Until now strategies to reverse hypertrophy have relied on the inhibition of prohypertrophic signaling pathways. Here we review signaling pathways of atrophy in the heart and we present evidence in support of the idea that activating proatrophic signaling pathways in the presence of prohypertrophic signaling may be an attractive strategy to reverse hypertrophy.
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Affiliation(s)
- Peter Razeghi
- University of Texas Houston Medical School, 6431 Fannin, MSB 1.246, Houston, TX 77030, USA
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Razeghi P, Buksinska-Lisik M, Palanichamy N, Stepkowski S, Frazier OH, Taegtmeyer H. Transcriptional regulators of ribosomal biogenesis are increased in the unloaded heart. FASEB J 2006; 20:1090-6. [PMID: 16770008 DOI: 10.1096/fj.06-5718com] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Mechanical unloading of the rat heart increases both protein synthesis and protein degradation. The transcriptional mechanism underlying increased protein synthesis during atrophic remodeling is not known. The aim of this study was to identify transcriptional regulators and the gene expression profile regulating protein synthesis in the unloaded rat heart and in the unloaded failing human heart. We measured DNA binding activity, transcript levels, and protein expression of transcriptional regulators of protein synthesis in a model of atrophic remodeling induced by heterotopic transplantation of the rat heart (duration 1 and 7 days). Using microarray analysis and quantitative RT-polymerase chain reaction, we found an increase in c-myc-regulated gene expression including an induction of ribosomal subunit messenger RNA's (RPS 10, RPL 21) and rRNA (18S). Consistent with the gene expression profile, DNA binding activity of c-myc and the nuclear protein concentration of its coactivator, upstream binding factor (UBF), increased in the atrophied heart whereas protein levels of the c-myc inhibitor MAD1 decreased. We found the same increase of ribosomal subunit messenger RNA and rRNA in 21 paired samples of failing human hearts obtained before and after left ventricular assist device treatment (mean duration: 157+/-31 days). In summary, mechanical unloading increases c-myc activity and c-myc-regulated gene expression in the rat heart. Changes in transcript levels of genes regulating ribosomal biogenesis in the unloaded rat heart resemble those found in the unloaded failing human heart. We concluded c-myc and c-myc-regulated gene expression are transcriptional regulators of protein synthesis during atrophic remodeling of the heart.
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Affiliation(s)
- Peter Razeghi
- Division of Cardiology, University of Texas Houston-Medical School, 6431 Fannin, MSB 1.222, Houston, Texas 77030, USA
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Razeghi P, Baskin KK, Sharma S, Young ME, Stepkowski S, Essop MF, Taegtmeyer H. Atrophy, hypertrophy, and hypoxemia induce transcriptional regulators of the ubiquitin proteasome system in the rat heart. Biochem Biophys Res Commun 2006; 342:361-4. [PMID: 16483544 DOI: 10.1016/j.bbrc.2006.01.163] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Accepted: 01/31/2006] [Indexed: 12/17/2022]
Abstract
BACKGROUND In skeletal muscle, transcript levels of proteins regulating the ubiquitin proteasome system (UPS) increase with atrophy and decrease with hypertrophy. Whether the same is true for heart muscle is not known. AIM OF THE STUDY We set out to characterize the transcriptional profile of regulators of the UPS during atrophy-, hypertrophy-, and hypoxia-induced remodeling of the heart. METHODS AND RESULTS Cardiac atrophy was induced by heterotopic transplantation of the rat heart. Left ventricular hypertrophy was induced by banding of the ascending aorta in rats. To study the effects of hypoxemia on the left ventricle, rats were exposed to hypobaric hypoxia. Transcript levels of six known regulators of the UPS, ubiquitin B (UbB), the ubiquitin conjugating enzymes UbcH2 and E2-14kDa, the ubiquitin ligases Mafbx/Atrogin-1 and MuRF-1, and the proteasomal subunit PSMB4 were measured using quantitative RT-PCR. Unloading-induced atrophy increased mRNA levels of UbB and decreased levels of both ubiquitin ligases. Transcript levels of all UPS genes investigated increased in the hypertrophied and hypoxic heart (with the exception of E2-14kDa). CONCLUSIONS Cardiac atrophy, hypertrophy, and hypoxemia all increase myocardial UbB expression, suggesting that UbB is a transcriptional marker for load-induced and hypoxia-mediated cardiac remodeling.
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Affiliation(s)
- Peter Razeghi
- Department of Internal Medicine, Division of Cardiology, The University of Texas Health Science Center, Houston, TX, USA
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