The effect of angiotensin II on myosin heavy chain expression in cultured myocardial cells

1996 ◽  
Vol 32 (9) ◽  
pp. 573-578 ◽  
Author(s):  
Noa Shalitin ◽  
Menahem Friedman ◽  
Hadassa Schlesinger ◽  
Yael Barhum ◽  
Maurice J. Levy ◽  
...  
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.


1993 ◽  
Vol 265 (1) ◽  
pp. H238-H243 ◽  
Author(s):  
D. L. Geenen ◽  
A. Malhotra ◽  
J. Scheuer

This study examined the direct effect of angiotensin II (ANG II) on cardiac muscle atrophy previously observed in the denervated rat heart. Rats with transplanted hearts were infused with normal saline (1 microliter/h) or a subpressor dose of ANG II dissolved in saline (3 micrograms.kg-1.h-1) for 1 wk. Left ventricular (LV) mass of transplanted hearts decreased by 29 and 18% in the saline-infused and ANG II-infused groups, respectively (P < 0.05). Total LV protein synthesis of the transplanted heart was 1.4 +/- 0.1 mg.LV-1.day-1 in the saline compared with 2.2 +/- 0.2 mg.LV-1.day-1 in the ANG II (P < 0.05) group. Heart rate and carotid systolic arterial pressures were not affected by ANG II infusion, and the decrease in alpha-myosin heavy chain normally observed in this model was unchanged between the two groups (61 +/- 3 and 66 +/- 1%, saline vs. ANG II). These data demonstrate that ANG II increases total cardiac protein synthesis in the adult heart, leading to an attenuation in cardiac atrophy. The failure of ANG II to prevent the shift from alpha- to beta-myosin heavy chain may be related to its lack of an effect on heart rate, since other interventions that affect myosin isoenzyme distribution also increase heart rate.


Nephron ◽  
2002 ◽  
Vol 90 (4) ◽  
pp. 477-483 ◽  
Author(s):  
Naobumi Mise ◽  
Kenjiro Kimura ◽  
Masahiko Kurabayashi ◽  
Ryozo Nagai ◽  
Toshihiro Okuda ◽  
...  

2020 ◽  
Vol 134 (3) ◽  
pp. 359-377
Author(s):  
Laia Cañes ◽  
Ingrid Martí-Pàmies ◽  
Carme Ballester-Servera ◽  
Adela Herraiz-Martínez ◽  
Judith Alonso ◽  
...  

Abstract Hypertensive cardiac hypertrophy (HCH) is a common cause of heart failure (HF), a major public health problem worldwide. However, the molecular bases of HCH have not been completely elucidated. Neuron-derived orphan receptor-1 (NOR-1) is a nuclear receptor whose role in cardiac remodelling is poorly understood. The aim of the present study was to generate a transgenic mouse over-expressing NOR-1 in the heart (TgNOR-1) and assess the impact of this gain-of-function on HCH. The CAG promoter-driven transgenesis led to viable animals that over-expressed NOR-1 in the heart, mainly in cardiomyocytes and also in cardiofibroblasts. Cardiomyocytes from TgNOR-1 exhibited an enhanced cell surface area and myosin heavy chain 7 (Myh7)/Myh6 expression ratio, and increased cell shortening elicited by electric field stimulation. TgNOR-1 cardiofibroblasts expressed higher levels of myofibroblast markers than wild-type (WT) cells (α 1 skeletal muscle actin (Acta1), transgelin (Sm22α)) and were more prone to synthesise collagen and migrate. TgNOR-1 mice experienced an age-associated remodelling of the left ventricle (LV). Angiotensin II (AngII) induced the cardiac expression of NOR-1, and NOR-1 transgenesis exacerbated AngII-induced cardiac hypertrophy and fibrosis. This effect was associated with the up-regulation of hypertrophic (brain natriuretic peptide (Bnp), Acta1 and Myh7) and fibrotic markers (collagen type I α 1 chain (Col1a1), Pai-1 and lysyl oxidase-like 2 (Loxl2)). NOR-1 transgenesis up-regulated two key genes involved in cardiac hypertrophy (Myh7, encoding for β-myosin heavy chain (β-MHC)) and fibrosis (Loxl2, encoding for the extracellular matrix (ECM) modifying enzyme, Loxl2). Interestigly, in transient transfection assays, NOR-1 drove the transcription of Myh7 and Loxl2 promoters. Our findings suggest that NOR-1 is involved in the transcriptional programme leading to HCH.


Genetics ◽  
1994 ◽  
Vol 137 (2) ◽  
pp. 483-498
Author(s):  
J Ahnn ◽  
A Fire

Abstract We have used available chromosomal deficiencies to screen for genetic loci whose zygotic expression is required for formation of body-wall muscle cells during embryogenesis in Caenorhabditis elegans. To test for muscle cell differentiation we have assayed for both contractile function and the expression of muscle-specific structural proteins. Monoclonal antibodies directed against two myosin heavy chain isoforms, the products of the unc-54 and myo-3 genes, were used to detect body-wall muscle differentiation. We have screened 77 deficiencies, covering approximately 72% of the genome. Deficiency homozygotes in most cases stain with antibodies to the body-wall muscle myosins and in many cases muscle contractile function is observed. We have identified two regions showing distinct defects in myosin heavy chain gene expression. Embryos homozygous for deficiencies removing the left tip of chromosome V fail to accumulate the myo-3 and unc-54 products, but express antigens characteristic of hypodermal, pharyngeal and neural development. Embryos lacking a large region on chromosome III accumulate the unc-54 product but not the myo-3 product. We conclude that there exist only a small number of loci whose zygotic expression is uniquely required for adoption of a muscle cell fate.


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