Article

A Wnt- and β-catenin-dependent pathway for mammalian cardiac myogenesis

Center for Cardiovascular Development and Department of Biochemistry, Baylor College of Medicine, Houston, TX 77030, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 06/2003; 100(10):5834-9. DOI: 10.1073/pnas.0935626100
Source: PubMed

ABSTRACT Acquisition of a cardiac fate by embryonic mesodermal cells is a fundamental step in heart formation. Heart development in frogs and avians requires positive signals from adjacent endoderm, including bone morphogenic proteins, and is antagonized by a second secreted signal, Wnt proteins, from neural tube. By contrast, mechanisms of mesodermal commitment to create heart muscle in mammals are largely unknown. In addition, Wnt-dependent signals can involve either a canonical beta-catenin pathway or other, alternative mediators. Here, we tested the involvement of Wnts and beta-catenin in mammalian cardiac myogenesis by using a pluripotent mouse cell line (P19CL6) that recapitulates early steps for cardiac specification. In this system, early and late cardiac genes are up-regulated by 1% DMSO, and spontaneous beating occurs. Notably, Wnt3A and Wnt8A were induced days before even the earliest cardiogenic transcription factors. DMSO induced biochemical mediators of Wnt signaling (decreased phosphorylation and increased levels of beta-catenin), which were suppressed by Frizzled-8Fc, a soluble Wnt antagonist. DMSO provoked T cell factor-dependent transcriptional activity; thus, induction of Wnt proteins by DMSO was functionally coupled. Frizzled-8Fc inhibited the induction of cardiogenic transcription factors, cardiogenic growth factors, and sarcomeric myosin heavy chains. Likewise, differentiation was blocked by constitutively active glycogen synthase kinase 3beta, an intracellular inhibitor of the Wntbeta-catenin pathway. Conversely, lithium chloride, which inhibits glycogen synthase kinase 3beta, and Wnt3A-conditioned medium up-regulated early cardiac markers and the proportion of differentiated cells. Thus, Wntbeta-catenin signaling is activated at the inception of mammalian cardiac myogenesis and is indispensable for cardiac differentiation, at least in this pluripotent model system.

0 Followers
 · 
105 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Wnt activity is a key regulator of cardiac progenitor cell self-renewal, differentiation and morphogenesis. However, Wnt inhibitory factor 1 (WIF1), a antagonists of Wnt signaling activity, its potential effects on heart development has not yet been approached by either in vivo or in vitro studies. Here, the expression of WIF1 was regulated in a different way in the dilated and hypertrophic cardiomyopathy heart from transgenic mice by mutations in cardiac troponin T, cTnTR141W and cTnTR92Q. The heart tissue specific transgenic mice of WIF1 was studied using M-mode echocardiography and histologic analyses. Production levels of an array of effectors and transcription factors that impact cellular organization and tissue morphology were measured. The effects of WIF1 on β-catenin pathway could be reversed by LiCl regarding signaling pathways and effector and respondent molecules in H9c2 cells, consistent with the expression levels of c-myc, natriuretic peptide precursor type B and skeletal muscle actin α1. Among the most noteworthy findings were that WIF1 impaired the function and structure of heart, and the effects on β-catenin pathway maybe the course of the former. It is anticipated that our findings will contribute to expansion of our understanding of WIF1 biological function on heart development and possible modes of treatment of heart diseases. Electronic supplementary materialThe online version of this article (doi:10.1007/s11248-013-9738-z) contains supplementary material, which is available to authorized users.
    Transgenic Research 08/2013; 22(6). DOI:10.1007/s11248-013-9738-z · 2.28 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Notch and Wnt/β-catenin signaling both play essential roles and interact closely in cardiomyocyte differentiation but the mechanism of interaction is largely unknown. Here we show that activation of Notch signaling in undifferentiated P19CL6 cells promoted cardiac differentiation, indicated by upregulated expression of early cardiac markers and activated the canonical Wnt pathway, suggested by augmented nuclear translocation of β-catenin. Further activation of the Notch pathway in early differentiating cells (at day 3) inhibited expression of a specific cardiac progenitor marker Islet1 but had no influence on β-catenin translocation. Notch signaling thus played biphasic roles in the early stage of cardiomyocyte differentiation and Wnt/β-catenin signaling. Unlike Notch signaling, Wnt signaling promoted cardiomyocyte differentiation and activated the Notch pathway in either undifferentiated or early differentiating cells. Additionally, β-catenin, recombination signal sequence binding protein-Jkappa (RBP-Jκ), and Notch1 intracellular domain (NICD-1) formed a transcriptional complex which was recruited to the Hes1 promoter region, indicating direct transcriptional regulation of Hes1. We thus document a specific reciprocal interaction between these two signaling pathways during early stage cardiac differentiation of P19CL6 cells.
    Journal of Cellular Biochemistry 02/2012; 113(2):629-39. DOI:10.1002/jcb.23390 · 3.37 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: During cardiac development, the heart produces the atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). These peptides are found in high levels in cardiomyocytes and, like a number of other embryonic genes, are up-regulated in both failing and hypertrophied ventricles. At the transcriptional level, BNP and ANP genes are regulated through RE1 regulatory element, which binds RE1-silencing transcription factor (REST). REST/NRSF-interacting LIM domain protein (RILP) is required for the nuclear targeting and function of REST. In this study, the role of RILP and REST in cardiomyocyte development using a model system was studied by analyzing the expression of RILP and REST as well as several cardiac-specific genes during P19CL6 cell differentiation. Effects of RILP overexpression and transcriptional regulation of RILP in differentiating P19CL6 cells were also studied. RILP expression is transiently reduced during P19CL6 cell differentiation; however, REST expression remains unchanged. This transient reduction in RILP expression correlates with de-repression of sarcomeric myosin heavy chain, a marker for cardiomyocyte differentiation. Reporter gene analysis shows that RILP gene is down-regulated through 5'-regulatory elements before cardiac-specific gene expression. These results suggest that RILP expression and function control REST action more so than does REST expression and is an important regulatory role in cardiomyocyte differentiation.
    Genes to Cells 01/2011; 16(1):90-100. DOI:10.1111/j.1365-2443.2010.01471.x · 2.86 Impact Factor

Preview

Download
0 Downloads
Available from