Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
XB-ART-51803
Mech Dev February 1, 2016; 139 31-41.

Ventricular cell fate can be specified until the onset of myocardial differentiation.

Caporilli S , Latinkic BV .


Abstract
The mechanisms that govern specification of various cell types that constitute vertebrate heart are not fully understood. Whilst most studies of heart development have utilised the mouse embryo, we have used an alternative model, embryos of the frog Xenopus laevis, which permits direct experimental manipulation of a non-essential heart. We show that in this model pluripotent animal cap explants injected with cardiogenic factor GATA4 mRNA express pan-myocardial as well as ventricular and proepicardial markers. We found that cardiac cell fate diversification, as assessed by ventricular and proepicardial markers, critically depends on tissue integrity, as it is disrupted by dissociation but can be fully restored by inhibition of the BMP pathway and partially by Dkk-1. Ventricular and proepicardial cell fates can also be restored in reaggregated GATA4-expressing cells upon transplantation into a host embryo. The competence of the host embryo to induce ventricular and proepicardial markers gradually decreases with the age of the transplant and is lost by the onset of myocardial differentiation at the late tailbud stage (st. 28). The influence of the host on the transplant was not limited to diversification of cardiac cell fates, but also included induction of growth and rhythmic beating, resulting in generation of a secondary heart-like structure. Our results additionally show that efficient generation of secondary heart requires normal axial patterning of the host embryo. Furthermore, secondary hearts can be induced in a wide range of locations within the host, arguing that the host embryo provides a permissive environment for development of cardiac patterning, growth and physiological maturation. Our results have implications for a major goal of cardiac regenerative medicine, differentiation of ventricular myocardium.

PubMed ID: 26776863
PMC ID: PMC4798847
Article link: Mech Dev
Grant support: [+]
Genes referenced: dkk1 gata4 myl3 myl7 tnni3


Article Images: [+] show captions
References:
Afouda, 2005, Pubmed, Xenbase [+]


Xenbase: The Xenopus laevis and X. tropicalis resource.
Version: 4.11.3


Major funding for Xenbase is provided by grant P41 HD064556