Cardiac arterial pole alignment is sensitive to FGF8 signaling in the pharynx

Dev Biol. 2006 Jul 15;295(2):486-97. doi: 10.1016/j.ydbio.2006.02.052. Epub 2006 Jun 12.


Morphogenesis of the cardiac arterial pole is dependent on addition of myocardium and smooth muscle from the secondary heart field and septation by cardiac neural crest cells. Cardiac neural crest ablation results in persistent truncus arteriosus and failure of addition of myocardium from the secondary heart field leading to malalignment of the arterial pole with the ventricles. Previously, we have shown that elevated FGF signaling after neural crest ablation causes depressed Ca2+ transients in the primary heart tube. We hypothesized that neural crest ablation results in elevated FGF8 signaling in the caudal pharynx that disrupts secondary heart field development. In this study, we show that FGF8 signaling is elevated in the caudal pharynx after cardiac neural crest ablation. In addition, treatment of cardiac neural crest-ablated embryos with FGF8b blocking antibody or an FGF receptor blocker rescues secondary heart field myocardial development in a time- and dose-dependent manner. Interestingly, reduction of FGF8 signaling in normal embryos disrupts myocardial secondary heart field development, resulting in arterial pole malalignment. These results indicate that the secondary heart field myocardium is particularly sensitive to FGF8 signaling for normal conotruncal development, and further, that cardiac neural crest cells modulate FGF8 signaling in the caudal pharynx.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antibodies / pharmacology
  • Antibodies / therapeutic use
  • Embryo, Mammalian
  • Fibroblast Growth Factor 8 / antagonists & inhibitors
  • Fibroblast Growth Factor 8 / physiology*
  • Heart / embryology*
  • Heart / growth & development
  • Heart Defects, Congenital / embryology
  • Heart Defects, Congenital / etiology
  • Mice
  • Morphogenesis*
  • Neural Crest / abnormalities
  • Pharynx / embryology*
  • Pharynx / metabolism
  • Signal Transduction*
  • Truncus Arteriosus, Persistent / embryology
  • Truncus Arteriosus, Persistent / etiology


  • Antibodies
  • Fgf8 protein, mouse
  • Fibroblast Growth Factor 8