scholarly journals Is BMP‐2 a component of the particulate matrix that is responsible for epithelial/mesenchymal transformation during heart development

2012 ◽  
Vol 26 (S1) ◽  
Author(s):  
Tarek H. Abd-Elhamid ◽  
Marianne L. Conway ◽  
Allan R. Sinning
Keyword(s):  
Heart Development ◽  
Particulate Matrix ◽  
Mesenchymal Transformation

scholarly journals β-Catenin is required for endothelial-mesenchymal transformation during heart cushion development in the mouse

2004 ◽  
Vol 166 (3) ◽  
pp. 359-367 ◽  
Author(s):  
Stefan Liebner ◽  
Anna Cattelino ◽  
Radiosa Gallini ◽  
Noemi Rudini ◽  
Monica Iurlaro ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Heart Development ◽  
Transcriptional Activity ◽  
Ex Vivo ◽  
Smooth Muscle Actin ◽  
Muscle Actin ◽  
Endocardial Cushions ◽  
Smad Phosphorylation ◽  
Mesenchymal Transformation

During heart development endocardial cells within the atrio-ventricular (AV) region undergo TGFβ-dependent epithelial-mesenchymal transformation (EMT) and invade the underlying cardiac jelly. This process gives rise to the endocardial cushions from which AV valves and part of the septum originate. In this paper we show that in mouse embryos and in AV explants TGFβ induction of endocardial EMT is strongly inhibited in mice deficient for endothelial β-catenin, leading to a lack of heart cushion formation. Using a Wnt-signaling reporter mouse strain, we demonstrated in vivo and ex vivo that EMT in heart cushion is accompanied by activation of β-catenin/TCF/Lef transcriptional activity. In cultured endothelial cells, TGFβ2 induces α-smooth muscle actin (αSMA) expression. This process was strongly reduced in β-catenin null cells, although TGFβ2 induced smad phosphorylation was unchanged. These data demonstrate an involvement of β-catenin/TCF/Lef transcriptional activity in heart cushion formation, and suggest an interaction between TGFβ and Wnt-signaling pathways in the induction of endothelial-mesenchymal transformation.

scholarly journals Positive and Negative Regulation of Epicardial–Mesenchymal Transformation during Avian Heart Development

2001 ◽  
Vol 234 (1) ◽  
pp. 204-215 ◽  
Author(s):  
Christopher J. Morabito ◽  
Robert W. Dettman ◽  
Javier Kattan ◽  
J.Michael Collier ◽  
James Bristow
Keyword(s):  
Heart Development ◽  
Negative Regulation ◽  
Mesenchymal Transformation

A novel role for VEGF in endocardial cushion formation and its potential contribution to congenital heart defects

Development ◽  
2001 ◽  
Vol 128 (9) ◽  
pp. 1531-1538 ◽  
Author(s):  
Y. Dor ◽  
T.D. Camenisch ◽  
A. Itin ◽  
G.I. Fishman ◽  
J.A. McDonald ◽  
...  
Keyword(s):  
Growth Factor ◽  
Heart Development ◽  
Heart Defects ◽  
Negative Regulator ◽  
Congenital Defects ◽  
Endocardial Cushion ◽  
Potential Contribution ◽  
Vegf Receptor ◽  
Endocardial Cushions ◽  
Mesenchymal Transformation

Normal cardiovascular development is exquisitely dependent on the correct dosage of the angiogenic growth factor and vascular morphogen vascular endothelial growth factor (VEGF). However, cardiac expression of VEGF is also robustly augmented during hypoxic insults, potentially mediating the well-established teratogenic effects of hypoxia on heart development. We report that during normal heart morphogenesis VEGF is specifically upregulated in the atrioventricular (AV) field of the heart tube soon after the onset of endocardial cushion formation (i.e. the endocardium-derived structures that build the heart septa and valves). To model hypoxia-dependent induction of VEGF in vivo, we conditionally induced VEGF expression in the myocardium using a tetracycline-regulated transgenic system. Premature induction of myocardial VEGF in E9.5 embryos to levels comparable with those induced by hypoxia prevented formation of endocardial cushions. When added to explanted embryonic AV tissue, VEGF fully inhibited endocardial-to-mesenchymal transformation. Transformation was also abrogated in AV explants subjected to experimental hypoxia but fully restored in the presence of an inhibitory soluble VEGF receptor 1 chimeric protein. Together, these results suggest a novel developmental role for VEGF as a negative regulator of endocardial-to-mesenchymal transformation that underlies the formation of endocardial cushions. Moreover, ischemia-induced VEGF may be the molecular link between hypoxia and congenital defects in heart septation.

scholarly journals Origin, Fate, and Function of Epicardium-Derived Cells (EPDCs) in Normal and Abnormal Cardiac Development

2007 ◽  
Vol 7 ◽  
pp. 1777-1798 ◽  
Author(s):  
Heleen Lie-Venema ◽  
Nynke M. S. van den Akker ◽  
Noortje A. M. Bax ◽  
Elizabeth M. Winter ◽  
Saskia Maas ◽  
...  
Keyword(s):  
Heart Development ◽  
Cardiac Development ◽  
Clinical Importance ◽  
Fiber Formation ◽  
Developmental Defect ◽  
Heart Tube ◽  
Atrioventricular Cushions ◽  
Mesenchymal Transformation ◽  
And Function ◽  
Myocardial Architecture

During heart development, cells of the primary and secondary heart field give rise to the myocardial component of the heart. The neural crest and epicardium provide the heart with a considerable amount of nonmyocardial cells that are indispensable for correct heart development. During the past 2 decades, the importance of epicardium-derived cells (EPDCs) in heart formation became increasingly clear. The epicardium is embryologically formed by the outgrowth of proepicardial cells over the naked heart tube. Following epithelial-mesenchymal transformation, EPDCs form the subepicardial mesenchyme and subsequently migrate into the myocardium, and differentiate into smooth muscle cells and fibroblasts. They contribute to the media of the coronary arteries, to the atrioventricular valves, and the fibrous heart skeleton. Furthermore, they are important for the myocardial architecture of the ventricular walls and for the induction of Purkinje fiber formation.Whereas the exact signaling cascades in EPDC migration and function still need to be elucidated, recent research has revealed several factors that are involved in EPDC migration and specialization, and in the cross-talk between EPDCs and other cells during heart development. Among these factors are the Ets transcription factors Ets-1 and Ets-2. New data obtained with lentiviral antisense constructs targeting Ets-1 and Ets-2 specifically in the epicardium indicate that both factors are independently involved in the migratory behavior of EPDCs. Ets-2 seems to be especially important for the migration of EPDCs into the myocardial wall, and to subendocardial positions in the atrioventricular cushions and the trabeculae.With respect to the clinical importance of correct EPDC development, the relation with coronary arteriogenesis has been noted well before. In this review, we also propose a role for EPDCs in cardiac looping, and emphasize their contribution to the development of the valves and myocardial architecture. Lastly, we focus on the congenital heart anomalies that might be caused primarily by an epicardial developmental defect.

scholarly journals Lack of endothelial cell survivin causes embryonic defects in angiogenesis, cardiogenesis, and neural tube closure

Blood ◽  
2007 ◽  
Vol 109 (11) ◽  
pp. 4742-4752 ◽  
Author(s):  
Femke Zwerts ◽  
Florea Lupu ◽  
Astrid De Vriese ◽  
Saskia Pollefeyt ◽  
Lieve Moons ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Neural Tube ◽  
Heart Development ◽  
Neural Tube Closure ◽  
Endocardial Cushions ◽  
Vascular Integrity ◽  
Apoptosis Protein ◽  
Mesenchymal Transformation ◽  
Tube Closure

Abstract We explored the physiologic role of endothelial cell apoptosis during development by generating mouse embryos lacking the inhibitor of apoptosis protein (IAP) survivin in endothelium. This was accomplished by intercrossing survivinlox/lox mice with mice expressing cre recombinase under the control of the endothelial cell specific tie1 promoter (tie1-cre mice). Lack of endothelial cell survivin resulted in embryonic lethality. Mutant embryos had prominent and diffuse hemorrhages from embryonic day 9.5 (E9.5) and died before E13.5. Heart development was strikingly abnormal. Survivin-null endocardial lineage cells could not support normal epithelial-mesenchymal transformation (EMT), resulting in hypoplastic endocardial cushions and in utero heart failure. In addition, 30% of mutant embryos had neural tube closure defects (NTDs) that were not caused by bleeding or growth retardation, but were likely due to alterations in the release of soluble factors from endothelial cells that otherwise support neural stem cell proliferation and neurulation. Thus, regulation of endothelial cell survival, and maintenance of vascular integrity by survivin are crucial for normal embryonic angiogenesis, cardiogenesis, and neurogenesis.

The Ultrastructure of Myocardial Cells in Normal and Cardiac Lethal Mutant Mexican Axolotls, (Ambystoma Mexicanum)

1970 ◽  
Vol 28 ◽  
pp. 62-63
Author(s):  
Larry F. Lemanski ◽  
Eldridge M. Bertke ◽  
J. T. Justus
Keyword(s):  
Fine Structure ◽  
Heart Development ◽  
Osmium Tetroxide ◽  
Picric Acid ◽  
Ambystoma Mexicanum ◽  
Recessive Mutation ◽  
Acid Mixture ◽  
Myocardial Cells ◽  
Lethal Mutant ◽  
Mexican Axolotl

A recessive mutation has been recently described in the Mexican Axolotl, Ambystoma mexicanum; in which the heart forms structurally, but does not contract (Humphrey, 1968. Anat. Rec. 160:475). In this study, the fine structure of myocardial cells from normal (+/+; +/c) and cardiac lethal mutant (c/c) embryos at Harrison's stage 40 was compared. The hearts were fixed in a 0.1 M phosphate buffered formaldehyde-glutaraldehyde-picric acid-styphnic acid mixture and were post fixed in 0.1 M s-collidine buffered 1% osmium tetroxide. A detailed study of heart development in normal and mutant embryos from stages 25-46 will be described elsewhere.

Reversal of cardiomyopathy resulting from prenatal exposure to ethanol

1984 ◽  
Vol 42 ◽  
pp. 716-717
Author(s):  
C. Uphoff ◽  
C. Nyquist-Battie
Keyword(s):  
Prenatal Exposure ◽  
Heart Development ◽  
Membrane Integrity ◽  
Ethanol Exposure ◽  
Prenatal Ethanol Exposure ◽  
Pathological Changes ◽  
Prenatally Exposed ◽  
Inner Mitochondrial Membrane ◽  
Fetal Alcohol ◽  
Newborn Mice

Fetal Alcohol Syndrone (FAS) is a syndrome with characteristic abnormalities resulting from prenatal exposure to ethanol. In many children with FAS syndrome gross pathological changes in the heart are seen with septal defects the most prevalent abnormality recorded. Few studies in animal models have been performed on the effects of ethanol on heart development. In our laboratory, it has been observed that prenatal ethanol exposure of Swiss albino mice results in abnormal cardiac muscle ultrastructure when mice were examined at birth and compared to pairfed and normal controls. Fig. 1 is an example of the changes that are seen in the ethanol-exposed animals. These changes include enlarged mitochondria with loss of inner mitochondrial membrane integrity and loss of myofibrils. Morphometric analysis substantiated the presence of these alterations from normal cardiac ultrastructure. The present work was undertaken to determine if the pathological changes seen in the newborn mice prenatally exposed to ethanol could be reversed with age and abstinence.

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