Increased Expression of a Homologue of Drosophila Tissue Polarity Gene “Frizzled” in Left Ventricular Hypertrophy in the Rat, as Identified by Subtractive Hybridization

doi:10.1006/jmcc.1996.0109

Journal of Molecular and Cellular Cardiology

Volume 28, Issue 5, May 1996, Pages 1187-1191

https://doi.org/10.1006/jmcc.1996.0109 Get rights and content

Abstract

The molecular mechanisms that govern the development of left ventricular hypertrophy are not fully elucidated. We performed a subtractive hybridization procedure to identify genes controlling this adaptive process. Using this approach, we isolated a rat homologue of Drosophila tissue polarity gene “frizzled” 2 (fz-2). The expression of this gene was quantified by competitive reverse transcriptase polymerase chain reactions. The expression was higher in hypertrophic left ventricles at all time points tested, reaching statistical significance at days 1 and 10. We conclude that thefz-2 gene, a highly conserved gene for which a role in intra- and intercellular communication has been described, may be involved in the spatial control of ventricular remodeling.

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Cited by (31)

Chronic β-adrenergic stimulation reverses depressed Ca handling in mice overexpressing inhibitor-2 of protein phosphatase 1
2018, Journal of Molecular and Cellular Cardiology
Citation Excerpt :
It was demonstrated that GSK3-mediated phosphorylation of β-catenin triggers its ubiquitination and degradation via the proteasome [39]. The upregulation of frizzled-2 in a rat pressure overload model suggested the stimulation of Wnt signaling in cardiac hypertrophy [40]. Opposite data were observed in mice that lack the dishevelled-1 gene indicating that interruption of Wnt/frizzled signaling has antihypertrophic effects [41].
A higher expression/activity of type 1 serine/threonine protein phosphatase 1 (PP1) may contribute to dephosphorylation of cardiac regulatory proteins triggering the development of heart failure.
Here, we tested the putatively protective effects of PP1 inhibitor-2 (I₂) overexpression using a heart failure model induced by chronic β-adrenergic stimulation.
Transgenic (TG) and wild-type (WT) mice were subjected to isoprenaline (ISO) or isotonic NaCl solution supplied via osmotic minipumps for 7 days. I₂ overexpression was associated with a depressed PP1 activity. Basal contractility was unchanged in catheterized mice and isolated cardiomyocytes between TG^NaCl and WT^NaCl. TG^ISO mice exhibited more fibrosis and a higher expression of hypertrophy marker proteins as compared to WT^ISO. After acute administration of ISO, the contractile response was accompanied by a higher sensitivity in TG^ISO as compared to WT^ISO. In contrast to basal contractility, the peak amplitude of [Ca]_i and SR Ca load were reduced in TG^NaCl as compared to WT^NaCl. These effects were normalized to WT levels after chronic ISO stimulation. Cardiomyocyte relaxation and [Ca]_i decay kinetics were hastened in TG^ISO as compared to WT^ISO, which can be explained by a higher phospholamban phosphorylation at Ser¹⁶. Chronic catecholamine stimulation was followed by an enhanced expression of GSK3β, whereas the phosphorylation at Ser⁹ was lower in TG as compared to the corresponding WT group. This resulted in a higher I₂ phosphorylation that may reactivate PP1.
Our findings suggest that the basal desensitization of β-adrenergic signaling and the depressed Ca handling in TG by inhibition of PP1 is restored by a GSK3β-dependent phosphorylation of I₂.
Knockdown of peroxiredoxin 5 inhibits the growth of osteoarthritic chondrocytes via upregulating Wnt/β-catenin signaling
2014, Free Radical Biology and Medicine
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For instance, Frizzled-2 is expressed in synovial tissue of arthritic cartilage [21]; it also influences cell proliferation and the response to activating stimuli. Elevated expression of Frizzled-2 has been linked to tissue regeneration and hyperplasia in an animal model of atherosclerosis [22]. Wnt-4 is expressed within developing joints [23,24] and it also has been found to be differentially expressed during specific stages of mesenchymal condensation and/or chondrocyte differentiation [24–27].
Peroxiredoxin 5 is a member of the peroxiredoxin family, which has been shown to act as an antioxidant whose main function is to reduce reactive oxygen species in cells. Peroxiredoxin 5 has been found to be abnormally elevated in human osteoarthritic chondrocytes. However, the detailed mechanism by which peroxiredoxin 5 modulates human osteoarthritic chondrocytes’ survival has not been elucidated. In the current study, we demonstrated that peroxiredoxin 5 knockdown activated osteoarthritic chondrocytes apoptosis, and decreased scavenging of endogenous reactive oxygen species. Furthermore, silencing of peroxiredoxin 5 resulted in an altered expression of proteins associated with Wnt signaling. Collectively, these results demonstrated that the regulatory effects of peroxiredoxin 5 can be partially attributed to Wnt/β-catenin signaling.
Fibroblast-mediated pathways in cardiac hypertrophy
2014, Journal of Molecular and Cellular Cardiology
Citation Excerpt :
However, the Wnt/Fzd pathway is activated during the development of cardiac hypertrophy. For example, the cardiomyocyte Fzd2 receptor and Dvl-1 is upregulated by pressure overload [73,74]. In mice, Dvl-1 knockout does not cause cardiomyocyte hypertrophy in response to catecholamine [74].
Under normal physiological conditions, cardiac fibroblasts are the primary producers of extracellular matrix and supply a mechanical scaffold for efficacious heart contractions induced by cardiomyocytes. In the hypertrophic heart, cardiac fibroblasts provide a pivotal contribution to cardiac remodeling. Many growth factors and extracellular matrix components secreted by cardiac fibroblasts induce and modify cardiomyocyte hypertrophy. Recent evidence revealed that cardiomyocyte–cardiac fibroblast communications are complex and multifactorial. Many growth factors and molecules contribute to cardiac hypertrophy via different roles that include induction of hypertrophy and the feedback hypertrophic response, fine-tuning of adaptive hypertrophy, limitation of left ventricular dilation, and modification of interstitial changes. This review focuses on recent work and topics and provides a mechanistic insight into cardiomyocyte–cardiac fibroblast communication in cardiac hypertrophy. This article is part of a Special Issue entitled "Myocyte-Fibroblast Signalling in Myocardium ".
Functions of the Wnt/β-catenin pathway in an anemia-induced zebrafish model of cardiomyopathy are location dependent
2011, Biochemical and Biophysical Research Communications
Citation Excerpt :
In addition to its multifaceted functions during cardiogenesis as well as its potential to induce cardiomyocyte hyperplasia [7,11], the Wnt/β-catenin pathway has been found to be involved in the hypertrophic response in mammalian models [12]. Humans with cardiac hypertrophy have increased levels of β-catenin in their hearts [13], and aortic banding (i.e., pressure overload) of rat hearts leads to increased frizzled expression [14]. Furthermore, downregulation of the pathway attenuates cardiac hypertrophy.
Recent evidence that the heart is not a terminally-differentiated organ has provided more credence to investigations of pathways involved in inducing cardiomyocyte (CM) hyperplasia as a therapy for heart disease. Here, we leveraged zebrafish as a novel vertebrate model of cardiomyopathy to explore the therapeutic potential based on the Wnt/β-catenin signaling. In the anemia-induced zebrafish model of cardiomyopathy (tr265), we detected differently regulated CM hyperplasia and CM hypertrophy in the compact region and the trabecular region. To assess the effects of the Wnt/β-catenin pathway on these two regions, the anemia line was crossed with heat shock-inducible transgenic fish to upregulate or downregulate the pathway. Upregulation resulted in increased cardiomyocyte hyperplasia in the heart and increased cardiomyocyte hypertrophy in the trabecular region, while downregulation resulted in reduced cardiomyocyte hyperplasia in the heart and reduced cardiomyocyte hypertrophy in the trabecular region. Importantly, upregulation of the pathway resulted in improved fish survival, while downregulation decreased it. In summary, our data suggested that (1) the compact region and the trabecular region respond differently during cardiac remodeling; (2) activation of the Wnt/β-catenin pathway might exert a cardioprotective function via promoting cardiomyocyte hyperplasia.
Stably overexpressed human Frizzled-2 signals through the β-catenin pathway and does not activate Ca<sup>2+</sup>-mobilization in Human Embryonic Kidney 293 cells
2009, Cellular Signalling
Signal transduction via the Frizzled family of seven-transmembrane receptors controls important developmental processes. Aberrant signaling caused by altered Frizzled receptor activity or by mutations in downstream signaling components has been implicated in several adult pathologies. A diverse array of intracellular signaling pathways has been suggested to transduce the signals exerted in cells when secreted ligands of the Wnt family bind to Frizzled receptors. Studies with a chimeric receptor composed of Frizzled-2 and the β2-adrenergic receptor have suggested that the binding of Wnt-5a to Frizzled-2 results in the activation of G proteins of the Gα_i family, the mobilization of calcium from intracellular stores and the induction of gene transcription through nuclear factor of activated T cells. In this report, we demonstrate by using β-lactamase reporter gene technology that full-length, wild-type human Frizzled-2 does not couple to calcium-mediated signaling in HEK293 cells following stimulation with purified recombinant mouse Wnt-5a. In contrast, when stimulated with recombinant mouse Wnt-3a, Frizzled-2 activates the canonical Wnt/Frizzled signaling pathway, involving the transcriptional modulator β-catenin. Our report underlines the importance of using cell lines stably overexpressing wild-type Frizzled receptors and the use of purified ligands when studying receptor pharmacology. This approach has allowed us to measure the half-maximal concentration for activation of human Frizzled-2 (1.5 ± 0.4 nM; avg. ± SD) and human Frizzled-1 (1.3 ± 0.5 nM) following stimulation by Wnt-3a. Our results suggest that there is receptor redundancy with regard to Wnt-3a reception. In addition, we introduce β-lactamase reporter gene technology as an alternative to luciferase-based reporters to measure Frizzled receptor modulation for the discovery of Frizzled receptor-interacting drugs.
The Wnt/frizzled pathway in cardiovascular development and disease: Friend or foe?
2008, European Journal of Pharmacology
Citation Excerpt :
This raises the question whether components of the Wnt/frizzled signaling pathway would be re-expressed in the hypertrophic left ventricle as well. The first indication that this indeed is the case came from a subtractive hybridization experiment performed in our lab, where we showed that frizzled-2 expression was upregulated during hypertrophic development in the rat heart (Blankesteijn et al., 1996). Recently, a positive correlation between left ventricular mass and frizzled-2 expression in the rat was described (Cerutti et al., 2006), which confirmed and expanded this initial observation.
Proteins from the Wnt family have been implicated in cell–cell communication in a wide variety of developmental and physiological processes. Wnt signaling is required for different aspects of cardiac and vascular development, including myocardial specification, cardiac morphogenesis and cardiac valve formation as well as endothelial and vascular smooth muscle cell proliferation. Defective Wnt signaling can result in different cardiac and vascular abnormalities. In the adult heart and blood vessels, Wnt signaling activity is quite low under normal conditions. However, this pathway is reactivated during the pathological cardiac remodeling induced by pressure overload, in injured arteries and after myocardial infarction. Genetically modified animal models have shown that inhibition of Wnt signaling results in increased angiogenesis, better infarct healing and an attenuated hypertrophic response of the heart. This suggests that pharmacological inhibition of Wnt signaling could provide a novel therapeutic strategy to prevent excessive cardiac and vascular remodeling.

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^☆: Please address all correspondence to: Dr W. M. Blankesteijn, Department of Pharmacology, CARIM, University of Limburg, P.O. Box 616, 6200 MD Maastricht, The Netherlands

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Rapid CommunicationIncreased Expression of a Homologue of Drosophila Tissue Polarity Gene “Frizzled” in Left Ventricular Hypertrophy in the Rat, as Identified by Subtractive Hybridization☆

Abstract

Rapid Communication
Increased Expression of a Homologue of Drosophila Tissue Polarity Gene “Frizzled” in Left Ventricular Hypertrophy in the Rat, as Identified by Subtractive Hybridization☆