Role of mesodermal FGF8 and FGF10 overlaps in the development of the arterial pole of the heart and pharyngeal arch arteries.
BACKGROUND
The genes encoding fibroblast growth factor (FGF) 8 and 10 are expressed in the anterior part of the second heart field that constitutes a population of cardiac progenitor cells contributing to the arterial pole of the heart. Previous studies of hypomorphic and conditional Fgf8 mutants show disrupted outflow tract (OFT) and right ventricle (RV) development, whereas Fgf10 mutants do not have detectable OFT defects.


OBJECTIVE
Our aim was to investigate functional overlap between Fgf8 and Fgf10 during formation of the arterial pole.


RESULTS
We generated mesodermal Fgf8; Fgf10 compound mutants with MesP1Cre. The OFT/RV morphology in these mutants was affected with variable penetrance; however, the incidence of embryos with severely affected OFT/RV morphology was significantly increased in response to decreasing Fgf8 and Fgf10 gene dosage. Fgf8 expression in the pharyngeal arch ectoderm is important for development of the pharyngeal arch arteries and their derivatives. We now show that Fgf8 deletion in the mesoderm alone leads to pharyngeal arch artery phenotypes and that these vascular phenotypes are exacerbated by loss of Fgf10 function in the mesodermal core of the arches.


CONCLUSIONS
These results show functional overlap of FGF8 and FGF10 signaling from second heart field mesoderm during development of the OFT/RV, and from pharyngeal arch mesoderm during pharyngeal arch artery formation, highlighting the sensitivity of these key aspects of cardiovascular development to FGF dosage.
Watanabe
Yusuke
Y
Department of Developmental Biology, URA CNRS 2578, Institut Pasteur, 25 rue du Dr. Roux 75015 Paris, France.
Miyagawa-Tomita
Sachiko
S
Vincent
Stéphane D
SD
Kelly
Robert G
RG
Moon
Anne M
AM
Buckingham
Margaret E
ME
D000818:Animals; D001934:Branchial Region / Q000002:abnormalities / Q000098:blood supply* / Q000196:embryology; D003433:Crosses, Genetic; D005318:Fetal Heart / Q000254:growth & development*; D051526:Fibroblast Growth Factor 10 / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051524:Fibroblast Growth Factor 8 / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D018628:Gene Dosage; D005838:Genotype; D006330:Heart Defects, Congenital / Q000196:embryology* / Q000235:genetics / Q000473:pathology; D006352:Heart Ventricles / Q000002:abnormalities / Q000196:embryology; D008648:Mesoderm / Q000196:embryology / Q000378:metabolism; D051379:Mice; D008817:Mice, Mutant Strains; D014694:Ventricular Outflow Obstruction / Q000196:embryology / Q000235:genetics
C496464:Fgf10 protein, mouse; C496457:Fgf8 protein, mouse; D051526:Fibroblast Growth Factor 10; D051524:Fibroblast Growth Factor 8