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

Development. 2006 Nov;133(22):4585-93. doi: 10.1242/dev.02597. Epub 2006 Oct 18.

Abstract

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.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

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

Substances

  • Transforming Growth Factor beta