Cranial and cardiac neural crest defects in endothelin-A receptor-deficient mice

TLDR

Neural crest cells arise in the dorsal neural tube and migrate extensively to form diverse neural and non‑neural tissues, yet the molecular interactions guiding cephalic neural crest development remain poorly understood. ETA receptor mRNA is expressed in neural‑crest‑derived ectomesenchymal cells of pharyngeal arches and cardiac outflow tissues, while ET‑1 ligand mRNA is expressed in arch epithelium, paraxial mesoderm‑derived arch core, and arch vessel endothelium. ETA‑deficient mice recapitulate human CATCH‑22/velocardiofacial syndrome with craniofacial and cardiovascular defects, show loss of goosecoid expression in pharyngeal arches, and reveal a novel genetic pathway for paracrine communication between cephalic neural crest cells and their ectodermal/mesodermal environment.

Abstract

ABSTRACT Neural crest cells arise in the dorsal aspect of the neural tube and migrate extensively to differentiate into a variety of neural and non-neural tissues. While interactions between neural crest cells and their local environments are required for the proper development of these tissues, little information is available about the molecular nature of the cell-cell interactions in cephalic neural crest development. Here we demonstrate that mice deficient for one type of endothelin receptor, ETA, mimic the human conditions collectively termed CATCH 22 or velocardiofacial syndrome, which include severe craniofacial deformities and defects in the cardiovascular outflow tract. We show that ETA receptor mRNA is expressed by the neural crest-derived ectomesenchymal cells of pharyngeal arches and cardiac outflow tissues, whereas ET-1 ligand mRNA is expressed by arch epithelium, paraxial mesoderm-derived arch core and the arch vessel endothelium. This suggests that paracrine interaction between neural crest-derived cells and both ectoderm and mesoderm is essential in forming the skeleton and connective tissue of the head. Further, we find that pharyngeal arch expression of goosecoid is absent in ETA receptor-deficient mice, placing the transcription factor as one of the possible downstream signals triggered by activation of the ETA receptor. These observations define a novel genetic pathway for inductive communication between cephalic neural crest cells and their environmental counterparts.