Tgfbeta signaling is required for atrioventricular cushion mesenchyme remodeling during in vivo cardiac development.

Jiao K, Langworthy M, Batts L, Brown CB, Moses HL, Baldwin HS
Development. 2006 133 (22): 4585-93

PMID: 17050629 · DOI:10.1242/dev.02597

The transforming growth factorbeta (Tgfbeta) signaling pathway plays crucial roles in many biological processes. To understand the role(s) of Tgfbeta signaling during cardiogenesis in vivo and to overcome the early lethality of Tgfbr2(-/-) embryos, we applied a Cre/loxp system to specifically inactivate Tgfbr2 in either the myocardium or the endothelium of mouse embryos. Our results show that Tgfbr2 in the myocardium is dispensable for cardiogenesis in most embryos. Contrary to the prediction from results of previous in vitro collagen gel assays, inactivation of Tgfbr2 in the endocardium does not prevent atrioventricular cushion mesenchyme formation, arguing against its essential role in epithelium-mesenchyme transformation in vivo. We further demonstrate that Tgfbeta signaling is required for the proper remodeling of the atrioventricular canal and for cardiac looping, and that perturbation in Tgfbeta signaling causes the double-inlet left ventricle (DILV) defect. Thus, our study provides a unique mouse genetic model for DILV, further characterization of which suggests a potential cellular mechanism for the defect.

MeSH Terms (13)

Animals Cell Differentiation Endocardial Cushion Defects Fluorescent Antibody Technique Heart In Situ Hybridization Mesoderm Mice Mice, Mutant Strains Microdissection Models, Animal Signal Transduction Transforming Growth Factor beta

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