Regulation of β myosin heavy chain, c-myc and c-fos proto-oncogenes in thyroid hormone-induced hypertrophy of the rat myocardium

1993 ◽  
Vol 84 (1) ◽  
pp. 61-67 ◽  
Author(s):  
N. K. Green ◽  
M. D. Gammage ◽  
J. A. Franklyn ◽  
A. M. Heagerty ◽  
M. C. Sheppard

1. In order to investigate the molecular mechanisms determining the hypertrophic response of the ventricular myocardium to thyroid hormone administration, changes in left and right ventricular expression of the c-myc, c-fos and H-ras proto-oncogenes in response to treatment with 3,3′,5-tri-iodothyronine were defined. 2. Adult female Wistar rats were treated with daily subcutaneous injections of 3,3′,5-tri-iodothyronine (50 μg) for 1, 3, 7 or 14 days (n = 6 in each treatment group) and the results from 3,3′,5-tri-iodothyronine-treated animals were compared with those obtained from untreated controls (n = 6). Changes in the weight of the left and right ventricles in response to 3,3′,5-tri-iodothyronine treatment were measured; changes in expression of the c-myc, c-fos and H-ras proto-oncogenes were determined in parallel by measurement of specific messenger RNAs by Northern and dot hybridization, as well as changes in expression of β myosin heavy chain messenger RNA. 3. Treatment with 3,3′,5-tri-iodothyronine resulted in increases in both left and right ventricular weights after 3 days, an effect maintained up to 14 days. Despite an increase in left ventricular weight, levels of β myosin heavy chain, c-myc, c-fos and H-ras mRNAs in the left ventricle were unchanged; in contrast, an increase in right ventricular weight was associated with increased expression of β myosin heavy chain, c-myc and c-fos messenger RNAs. 4. These specific ventricular changes in gene expression, in the face of a hypertrophic response of both ventricles to 3,3′,5-tri-iodothyronine, suggest that the cardiac growth response to thyroid hormones reflects the well-documented secondary haemodynamic influences rather than direct gene regulatory actions of 3,3′,5-tri-iodothyronine at the transcriptional level on the genes studied. Changes in right ventricular proto-oncogene and β myosin heavy chain expression may in turn reflect an increase in right ventricular pressure load.

1989 ◽  
Vol 15 (4) ◽  
pp. 565-577 ◽  
Author(s):  
Wolfgang H. Dillmann ◽  
Alice Barrieux ◽  
Ravi Shanker

1990 ◽  
Vol 265 (11) ◽  
pp. 6489-6493
Author(s):  
B E Markham ◽  
R W Tsika ◽  
J J Bahl ◽  
P G Anderson ◽  
E Morkin

2006 ◽  
Vol 84 (8-9) ◽  
pp. 935-941 ◽  
Author(s):  
Baohua Wang ◽  
Jingping Ouyang ◽  
Zhengyuan Xia

Thyroid hormone-induced cardiac hypertrophy is similar to that observed in physiological hypertrophy, which is associated with high cardiac contractility and increased α-myosin heavy chain (α-MHC, the high ATPase activity isoform) expression. In contrast, angiotensin II (Ang II) induces an increase in myocardial mass with a compromised contractility accompanied by a shift from α-MHC to the fetal isoform β-MHC (the low ATPase activity isoform), which is considered as a pathological hypertrophy and inevitably leads to the development of heart failure. The present study is designed to assess the effect of thyroid hormone on angiotensin II-induced hypertrophic growth of cardiomyocytes in vitro. Cardiomyocytes were prepared from hearts of neonatal Wistar rats. The effects of Ang II and 3,3′,5-triiodo-thyronine (T3) on incorporations of [3H]-thymine and [3H]-leucine, MHC isoform mRNA expression, PKC activity, and PKC isoform protein expression were studied. Ang II enhanced [3H]-leucine incorporation, β-MHC mRNA expression, PKC activity, and PKCε expression and inhibited α-MHC mRNA expression in cardiomyocytes. T3 treatment prevented Ang II-induced increases in PKC activity, PKCε, and β-MHC mRNA overexpression and favored α-MHC mRNA expression. Thyroid hormone appears to be able to reprogram gene expression in Ang II-induced cardiac hypertrophy, and a PKC signal pathway may be involved in such remodeling process.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
A M C Koop ◽  
R F Videira ◽  
L Ottaviani ◽  
E M Poels ◽  
K W Van De Kolk ◽  
...  

Abstract Introduction Heart and neural crest derivatives expressed-2 (Hand2) has been identified as an important embryonic basic helix-loop-helix-transcription factor, with different functions in the development of the first and second heart field, from which the left and right ventricle originate, respectively. Our previous work revealed that Hand2, under conditions of left ventricular (LV) pressure overload, is re-expressed in the adult heart and activates a “fetal gene” program contributing to pathological cardiac remodeling. Ablation of cardiac expression of Hand2 resulted in protection to cardiac stress and attenuated maladaptive remodeling. Purpose In this study, we aimed at unraveling the role of Hand2 during cardiac remodeling in response to right ventricular (RV) pressure overload induced by pulmonary artery banding (PAB). Methods Hand2F/F and MCM− Hand2F/F mice were treated with tamoxifen (control and knockout, respectively) and subjected to six weeks of RV pressure overload induced by PAB. Echocardiographic and MRI derived hemodynamic parameters, and molecular remodelling were assessed for experimental groups and compared to sham-operated controls (Fig. 1a). RNA sequencing and gene ontology enrichment analysis were performed to compare the dysregulated genes between the pressure overloaded RV of the control and Hand2 knockout mice. Results After six weeks of increased pressure load (Fig. 1b), levels of Hand2 increased in the control banded animals but, as expected, remained absent in the knockout hearts (Fig. 1c). In contrast to the what was previously observed for the pressure overloaded LV, in the pressure loaded RV, Hand2 depletion resulted in more severe remodelling and dysfunction as reflected by increased hypertrophic growth, increased RV end-diastolic and end-systolic volumes as well as decreased RV ejection fraction (Fig. 1d–g). In addition, RNA sequencing revealed a distinct set of genes that are dysregulated in the pressure-overloaded RV, compared to the previously described pressure-overloaded LV. These include components of the extracellular matrix structure, collagen assembly and organization and several types of collagens. Genes associated with inflammation response, adhesion and muscle organization were also affected in the RV of the Hand2 KO mice (Fig. 1h). Figure 1 Conclusion Cardiac-specific depletion of Hand2 is associated with severe cardiac dysfunction in conditions of RV pressure overload. While inhibiting Hand2 expression can prevent cardiac dysfunction in conditions of LV pressure overload, the same does not hold true for conditions of RV pressure overload. This study highlights the need to better understand the molecular mechanisms driving pathological remodelling of the RV, in contrast to the LV, in order to better diagnose and treat patients with RV or LV failure.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Christoph Haller ◽  
Mark K. Friedberg ◽  
Michael A. Laflamme

AbstractRight ventricular (RV) failure is a commonly encountered problem in patients with congenital heart disease but can also be a consequence of left ventricular disease, primary pulmonary hypertension, or RV-specific cardiomyopathies. Improved survival of the aforementioned pathologies has led to increasing numbers of patients suffering from RV dysfunction, making it a key contributor to morbidity and mortality in this population. Currently available therapies for heart failure were developed for the left ventricle (LV), and there is clear evidence that LV-specific strategies are insufficient or inadequate for the RV. New therapeutic strategies are needed to address this growing clinical problem, and stem cells show significant promise. However, to properly evaluate the prospects of a potential stem cell-based therapy for RV failure, one needs to understand the unique pathophysiology of RV dysfunction and carefully consider available data from animal models and human clinical trials. In this review, we provide a comprehensive overview of the molecular mechanisms involved in RV failure such as hypertrophy, fibrosis, inflammation, changes in energy metabolism, calcium handling, decreasing RV contractility, and apoptosis. We also summarize the available preclinical and clinical experience with RV-specific stem cell therapies, covering the broad spectrum of stem cell sources used to date. We describe two different scientific rationales for stem cell transplantation, one of which seeks to add contractile units to the failing myocardium, while the other aims to augment endogenous repair mechanisms and/or attenuate harmful remodeling. We emphasize the limitations and challenges of regenerative strategies, but also highlight the characteristics of the failing RV myocardium that make it a promising target for stem cell therapy.


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