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Abstract
There are multiple intrinsic mechanisms for diastolic dysfunction ranging from molecular to structural derangements in ventricular myocardium. The molecular mechanisms regulating the progression from normal diastolic function to severe dysfunction still remain poorly understood. Recent studies suggest a potentially important role of core cardio-enriched transcription factors (TFs) in the control of cardiac diastolic function in health and disease through their ability to regulate the expression of target genes involved in the process of adaptive and maladaptive cardiac remodeling. The current relevant findings on the role of a variety of such TFs (TBX5, GATA-4/6, SRF, MYOCD, NRF2, and PITX2) in cardiac diastolic dysfunction and failure are updated, emphasizing their potential as promising targets for novel treatment strategies. In turn, the new animal models described here will be key tools in determining the underlying molecular mechanisms of disease. Since diastolic dysfunction is regulated by various TFs, which are also involved in cross talk with each other, there is a need for more in-depth research from a biomedical perspective in order to establish efficient therapeutic strategies.
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Torrado M, Franco D, Hernández-Torres F, Crespo-Leiro MG, Iglesias-Gil C, Castro-Beiras A, Mikhailov AT. Pitx2c is reactivated in the failing myocardium and stimulates myf5 expression in cultured cardiomyocytes. PLoS One 2014; 9:e90561. [PMID: 24595098 PMCID: PMC3942452 DOI: 10.1371/journal.pone.0090561] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 02/01/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Pitx2 (paired-like homeodomain 2 transcription factor) is crucial for heart development, but its role in heart failure (HF) remains uncertain. The present study lays the groundwork implicating Pitx2 signalling in different modalities of HF. METHODOLOGY/PRINCIPAL FINDINGS A variety of molecular, cell-based, biochemical, and immunochemical assays were used to evaluate: (1) Pitx2c expression in the porcine model of diastolic HF (DHF) and in patients with systolic HF (SHF) due to dilated and ischemic cardiomyopathy, and (2) molecular consequences of Pitx2c expression manipulation in cardiomyocytes in vitro. In pigs, the expression of Pitx2c, physiologically downregulated in the postnatal heart, is significantly re-activated in left ventricular (LV) failing myocardium which, in turn, is associated with increased expression of a restrictive set of Pitx2 target genes. Among these, Myf5 was identified as the top upregulated gene. In vitro, forced expression of Pitx2c in cardiomyocytes, but not in skeletal myoblasts, activates Myf5 in dose-dependent manner. In addition, we demonstrate that the level of Pitx2c is upregulated in the LV-myocardium of SHF patients. CONCLUSIONS/SIGNIFICANCE The results provide previously unrecognized evidence that Pitx2c is similarly reactivated in postnatal/adult heart at distinct HF phenotypes and suggest that Pitx2c is involved, directly or indirectly, in the regulation of Myf5 expression in cardiomyocytes.
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Affiliation(s)
- Mario Torrado
- Institute of Health Sciences, University of La Coruña, La Coruña, Spain
| | - Diego Franco
- Department of Experimental Biology, University of Jaen, Jaen, Spain
| | | | | | | | - Alfonso Castro-Beiras
- Institute of Health Sciences, University of La Coruña, La Coruña, Spain
- University Hospital Center of La Coruña, La Coruña, Spain
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Takeishi Y, Walsh RA. Cardiac hypertrophy and failure: lessons learned from genetically engineered mice. ACTA PHYSIOLOGICA SCANDINAVICA 2001; 173:103-11. [PMID: 11678732 DOI: 10.1046/j.1365-201x.2001.00890.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Congestive heart failure is a major and growing public health problem. Because of improved survival of myocardial infarction patients produced by thrombolytic therapy or per-cutaneous revascularization it represents the only form of cardiovascular disease with significantly increased incidence and prevalence. Clinicians view this clinical syndrome as the final common pathway of diverse pathologies such as myocardial infarction and haemodynamic overload. Insights into mechanisms for heart failure historically derived from physiological and biochemical studies which identified compensatory adaptations for the haemodynamic burden associated with the pathological condition including utilization of the Frank Starling mechanism, augmentation of muscle mass, and neurohormonal activation to increase contractility. Therapy has largely been phenomenological and designed to prevent or limit the deleterious effects of these compensatory processes. More recently insights from molecular and cell biology have contributed to a more mechanistic understanding of potential causes of cardiac hypertrophy and failure. Many different analytical approaches have been employed for this purpose. These include the use of conventional animal models which permit serial observation of the onset and progression of heart failure and a sequential analysis of underlying biochemical and molecular events. Neonatal murine cardiomyocytes have been a powerful tool to examine in vitro subcellular mechanisms devoid of the confounding functional effects of multicellular preparations and heterogeneity of cell type. Finally, significant progress has been made by utilizing tissue from human cardiomyopathic hearts explanted at the time of orthotopic transplantation. Each of these methods has significant advantages and disadvantages. Arguably the greatest advance in our understanding of cardiac hypertrophy and failure over the past decade has been the exploitation of genetically engineered mice as biological reagents to study in vivo the effects of alterations in the murine genome. The power of this approach, in principle, derives from the ability to precisely overexpress or ablate a gene of interest and examine the phenotypic consequences in a cardiac specific post-natal manner. In contrast to conventional animal models of human disease which employ some form of environmental stress, genetic engineering involves a signal known molecular perturbation which produces the phenotype.
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Affiliation(s)
- Y Takeishi
- Department of Medicine, Case Western Reserve University and University Hospital of Cleveland, Cleveland, OH 44106-5029, USA
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Chien KR. Meeting Koch's postulates for calcium signaling in cardiac hypertrophy. J Clin Invest 2000; 105:1339-42. [PMID: 10811840 PMCID: PMC315474 DOI: 10.1172/jci10079] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- K R Chien
- University of California at San Diego (UCSD)-Salk Program in Molecular Medicine, UCSD School of Medicine, Basic Science Building 0613-C, 9500 Gilman Drive, La Jolla, California 92093, USA.
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Bisognano JD, Weinberger HD, Bohlmeyer TJ, Pende A, Raynolds MV, Sastravaha A, Roden R, Asano K, Blaxall BC, Wu SC, Communal C, Singh K, Colucci W, Bristow MR, Port DJ. Myocardial-directed overexpression of the human beta(1)-adrenergic receptor in transgenic mice. J Mol Cell Cardiol 2000; 32:817-30. [PMID: 10775486 DOI: 10.1006/jmcc.2000.1123] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The beta(1)-adrenergic receptor (AR) is the dominant subtype in non-failing and failing myocardium. beta(1)-AR signaling, by the endogenous neurotransmitter norepinephrine, is central to the regulation of myocardial contractility. In heart failure, the beta(1)-AR undergoes subtype-selective downregulation which may protect against the increased cardiac adrenergic drive associated with this pathophysiological state. To examine the hypothesis that chronically increased beta(1)-AR mediated signaling has adverse myocardial effects, transgenic mice overexpressing the human beta(1)-AR in a cardiac-selective context were produced, utilizing an alpha-myosin heavy chain (MHC) promoter. In these mice, beta(1)-AR protein abundance was approximately 24-46-fold (1-2 pmol/mg protein) that of wild-type mice. Histopathological examination of young (4 months old) and old (approximately 9 months old) transgenic mouse hearts consistently demonstrated large areas of interstitial replacement fibrosis, marked myocyte hypertrophy and myofibrilar disarray. In addition, increased expression of the pre-apoptotic marker, Bax, was observed coincident with regions of fibrosis accompanied by an increased apoptotic index, as measured by TUNEL assay. Older non-transgenic mice exhibited a slight tendency towards a decreased fractional shortening, whereas older beta(1)-AR transgenic mice had a marked reduction in fractional shortening (%FS approximately 30) as determined by echocardiography. Additionally, older beta(1)-AR transgenic mice had an increased left ventricular chamber size. In summary, cardiac-directed overexpression of the human beta(1)-AR in transgenic mice leads to a significant histopathological phenotype with no apparent functional consequence in younger mice and a variable degree of cardiac dysfunction in older animals. This model system may ultimately prove useful for investigating the biological basis of adrenergically-mediated myocardial damage in humans.
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Affiliation(s)
- J D Bisognano
- Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado, 80262, USA
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Asai K, Yang GP, Geng YJ, Takagi G, Bishop S, Ishikawa Y, Shannon RP, Wagner TE, Vatner DE, Homcy CJ, Vatner SF. Beta-adrenergic receptor blockade arrests myocyte damage and preserves cardiac function in the transgenic G(salpha) mouse. J Clin Invest 1999; 104:551-8. [PMID: 10487769 PMCID: PMC408547 DOI: 10.1172/jci7418] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Transgenic (TG) mice with cardiac G(salpha) overexpression exhibit enhanced inotropic and chronotropic responses to sympathetic stimulation, but develop cardiomyopathy with age. We tested the hypothesis that cardiomyopathy in TG mice with G(salpha) overexpression could be averted with chronic beta-adrenergic receptor (beta-AR) blockade. TG mice and age-matched wild-type littermates were treated with the beta-AR blocker propranolol for 6-7 months, starting at a time when the cardiomyopathy was developing but was not yet severe enough to induce significant cardiac depression (9.5 months of age), and ending at a time when cardiac depression and cardiomyopathy would have been clearly manifest (16 months of age). Propranolol treatment, which can induce cardiac depression in the normal heart, actually prevented cardiac dilation and the depressed left ventricular function characteristic of older TG mice, and abolished premature mortality. Propranolol also prevented the increase in myocyte cross-sectional area and myocardial fibrosis. Myocyte apoptosis, already apparent in 9-month-old TG mice, was actually eliminated by chronic propranolol. This study indicates that chronic sympathetic stimulation over an extended period is deleterious and results in cardiomyopathy. Conversely, beta-AR blockade is salutary in this situation and can prevent the development of cardiomyopathy.
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MESH Headings
- Adenylyl Cyclases/metabolism
- Adrenergic beta-Antagonists/therapeutic use
- Animals
- Blood Pressure
- Cardiomyopathy, Dilated/diagnostic imaging
- Cardiomyopathy, Dilated/genetics
- Cardiomyopathy, Dilated/pathology
- Cardiomyopathy, Dilated/prevention & control
- Cyclic AMP/biosynthesis
- Endomyocardial Fibrosis/diagnostic imaging
- Endomyocardial Fibrosis/genetics
- Endomyocardial Fibrosis/pathology
- Endomyocardial Fibrosis/prevention & control
- Enzyme Activation
- Female
- GTP-Binding Protein alpha Subunits, Gs/biosynthesis
- GTP-Binding Protein alpha Subunits, Gs/genetics
- Gene Expression Regulation
- Heart Rate
- Hypertrophy
- Male
- Mice
- Mice, Transgenic
- Myocardium/pathology
- Myosin Heavy Chains/genetics
- Promoter Regions, Genetic
- Propranolol/therapeutic use
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/physiology
- Recombinant Fusion Proteins/biosynthesis
- Recombinant Fusion Proteins/genetics
- Signal Transduction/drug effects
- Signal Transduction/genetics
- Ultrasonography
- Ventricular Dysfunction, Left/diagnostic imaging
- Ventricular Dysfunction, Left/genetics
- Ventricular Dysfunction, Left/pathology
- Ventricular Dysfunction, Left/prevention & control
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Affiliation(s)
- K Asai
- Weis Center for Research, Penn State College of Medicine, Danville, Pennsylvania 17822, USA
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Honda H, Harada K, Komuro I, Terasaki F, Ueno H, Tanaka Y, Kawamura K, Yazaki Y, Hirai H. Heart-specific activation of LTK results in cardiac hypertrophy, cardiomyocyte degeneration and gene reprogramming in transgenic mice. Oncogene 1999; 18:3821-30. [PMID: 10445845 DOI: 10.1038/sj.onc.1202736] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Leukocyte tyrosine kinase (LTK) is a receptor-type protein tyrosine kinase belonging to the insulin receptor superfamily. To elucidate its biological role, we generated transgenic mice expressing LTK under the control of cytomegarovirus enhancer and beta-actin promoter. The transgenic mice exhibited growth retardation and most of the transgenic mice died within several months after birth. Interestingly, although LTK was expressed in several major organs, the activation (tyrosine-phosphorylation, kinase activity, and multimerization) of LTK was observed selectively in the heart, where LTK was localized on intracellular membrane, presumably on endoplasmic reticulum. Echocardiography showed that the transgenic heart underwent severe concentric hypertrophy, which resulted in reduced cardiac output, low blood pressure, and increased heart rate. Histological examination of the heart exhibited focal degeneration of cardiomyocytes. These histological changes were considered to be due to apoptosis, based on the finding that the sarcolemmas of the degenerative cardiomyocytes were well preserved. In addition, expression of fetal genes, such as atrial natriuretic peptide and skeletal alpha-actin, was markedly induced in the transgenic heart. These results indicate that a certain tissue-specific mechanism of activating LTK exists in the heart and that the activated LTK resulted in cardiac hypertrophy, cardiomyocyte degeneration and gene reprogramming. These findings will provide novel insights into the activating mechanism and biological role of LTK in vivo.
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Affiliation(s)
- H Honda
- Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan
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Kessler PD, Byrne BJ. Myoblast cell grafting into heart muscle: cellular biology and potential applications. Annu Rev Physiol 1999; 61:219-42. [PMID: 10099688 DOI: 10.1146/annurev.physiol.61.1.219] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This review surveys a wide range of cellular and molecular approaches to strengthening the injured or weakened heart, focusing on strategies to replace dysfunctional, necrotic, or apoptotic cardiomyocytes with new cells of mesodermal origin. A variety of cell types, including myogenic cell lines, adult skeletal myoblasts, immoratalized atrial cells, embryonic and adult cardiomyocytes, embryonic stem cells, tetratoma cells, genetically altered fibroblasts, smooth muscle cells, and bone marrow-derived cells have all been proposed as useful cells in cardiac repair and may have the capacity to perform cardiac work. We focus on the implantation of mesodermally derived cells, the best developed of the options. We review the developmental and cell biology that have stimulated these studies, examine the limitations of current knowledge, and identify challenges for the future, which we believe are considerable.
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Affiliation(s)
- P D Kessler
- Peter Belfer Cardiac Laboratory, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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Affiliation(s)
- V J Kadambi
- Department of Pharmacology and Cell Biophysics, University of Cincinnati, College of Medicine, Ohio 45267-0575, USA
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Gupta M, Gupta MP, Arcilla RA. Molecular regulation of cardiac myogenesis and morphology during development. PROGRESS IN PEDIATRIC CARDIOLOGY 1998. [DOI: 10.1016/s1058-9813(99)00003-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Abstract
Since its discovery in 1963, cyclic GMP (cGMP) has been shown to be a ubiquitous second messenger. The enzymes that catalyze the formation of cGMP from GTP, guanylyl cyclases, exist in soluble and particulate isoforms. An explosion in the number of known isoforms, gene disruption, identification of new inhibitors and activators and finally the resolution of the structure of adenylyl cyclases have all provided important clues about the structure and function of guanylyl cyclases. This article gives a brief review of the recent developments in the field of guanylyl cyclase research.
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Affiliation(s)
- B J Wedel
- Howard Hughes Medical Institute and Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75235-9050, USA
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Fentzke RC, Korcarz CE, Lang RM, Lin H, Leiden JM. Dilated cardiomyopathy in transgenic mice expressing a dominant-negative CREB transcription factor in the heart. J Clin Invest 1998; 101:2415-26. [PMID: 9616213 PMCID: PMC508831 DOI: 10.1172/jci2950] [Citation(s) in RCA: 198] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Idiopathic-dilated cardiomyopathy (IDC) is a common primary myocardial disease of unknown etiology characterized by progressive biventricular failure, cardiac dilatation, and premature mortality. Here we show that transgenic mice expressing a dominant-negative form of the CREB transcription factor (CREBA133) under the control of the cardiac myocyte-specific alpha-MHC promoter develop dilated cardiomyopathy that closely resembles many of the anatomical, physiological, and clinical features of human IDC. Between 2 and 20 wk of age, these mice develop four chamber cardiac dilatation, decreased systolic and diastolic left ventricular function, and attenuated contractile responses to the beta-adrenergic agonist, isoproterenol. Histologically, the CREBA133 hearts demonstrated both atrophic and hypertrophied fibers as well as significant interstitial fibrosis. These anatomical and hemodynamic changes were associated with hepatic congestion and peripheral edema, intracardiac thrombi, and premature mortality. Taken together, these results implicate CREB as an important regulator of cardiac myocyte function and provide a genetic model of dilated cardiomyopathy which should facilitate studies of both the pathogenesis and therapy of this clinically important disorder.
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Affiliation(s)
- R C Fentzke
- Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA
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Sussman MA, Welch S, Cambon N, Klevitsky R, Hewett TE, Price R, Witt SA, Kimball TR. Myofibril degeneration caused by tropomodulin overexpression leads to dilated cardiomyopathy in juvenile mice. J Clin Invest 1998; 101:51-61. [PMID: 9421465 PMCID: PMC508539 DOI: 10.1172/jci1167] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Loss of myofibril organization is a common feature of chronic dilated and progressive cardiomyopathy. To study how the heart compensates for myofibril degeneration, transgenic mice were created that undergo progressive loss of myofibrils after birth. Myofibril degeneration was induced by overexpression of tropomodulin, a component of the thin filament complex which determines and maintains sarcomeric actin filament length. The tropomodulin cDNA was placed under control of the alpha-myosin heavy chain gene promoter to overexpress tropomodulin specifically in the myocardium. Offspring with the most severe phenotype showed cardiomyopathic changes between 2 and 4 wk after birth. Hearts from these mice present characteristics consistent with dilated cardiomyopathy and a failed hypertrophic response. Histological analysis showed widespread loss of myofibril organization. Confocal microscopy of isolated cardiomyocytes revealed intense tropomodulin immunoreactivity in transgenic mice together with abnormal coincidence of tropomodulin and alpha-actinin reactivity at Z discs. Contractile function was compromised severely as determined by echocardiographic analyses and isolated Langendorff heart preparations. This novel experimentally induced cardiomyopathy will be useful for understanding dilated cardiomyopathy and the effect of thin filament-based myofibril degeneration upon cardiac structure and function.
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Affiliation(s)
- M A Sussman
- The Children's Hospital and Research Foundation, Cincinnati, Ohio 45229, USA.
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Murry CE, Kay MA, Bartosek T, Hauschka SD, Schwartz SM. Muscle differentiation during repair of myocardial necrosis in rats via gene transfer with MyoD. J Clin Invest 1996; 98:2209-17. [PMID: 8941636 PMCID: PMC507669 DOI: 10.1172/jci119030] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Myocardial infarcts heal by scar formation because there are no stem cells in myocardium, and because adult myocytes cannot divide and repopulate the wound. We sought to redirect the heart to form skeletal muscle instead of scar by transferring the myogenic determination gene, MyoD, into cardiac granulation (wound repair) tissue. A replication-defective adenovirus was constructed containing MyoD under transcriptional control of the Rous sarcoma virus long terminal repeat. The virus converted cultured cardiac fibroblasts to skeletal muscle, indicated by expression of myogenin and skeletal myosin heavy chains (MHCs). To determine if MyoD could induce muscle differentiation in vivo, we injected 2 x 10(9) or 10(10) pfu of either the MyoD or a control beta-galactosidase adenovirus into healing rat hearts, injured 1 wk previously by freeze-thaw. After receiving the lower viral dose, cardiac granulation tissue expressed MyoD mRNA and protein, but did not express myogenin or skeletal MHC. When the higher dose of virus was administered, double immunostaining showed that cells in reparative tissue expressed both myogenin and embryonic skeletal MHC. No muscle differentiation occurred after beta-galactosidase transfection. Thus, MyoD gene transfer can induce skeletal muscle differentiation in healing heart lesions. Modifications of this strategy might eventually provide new contractile tissue to repair myocardial infarcts.
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Affiliation(s)
- C E Murry
- Department of Pathology, University of Washington, Seattle 98195, USA.
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