An essential role for Notch in neural crest during cardiovascular development and smooth muscle differentiation
Frances A. High, … , Warren S. Pear, Jonathan A. Epstein
Frances A. High, … , Warren S. Pear, Jonathan A. Epstein
Published February 1, 2007
Citation Information: J Clin Invest. 2007;117(2):353-363. https://doi.org/10.1172/JCI30070.
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Research Article

An essential role for Notch in neural crest during cardiovascular development and smooth muscle differentiation

Abstract

The cardiac outflow tract develops as a result of a complex interplay among several cell types, including cardiac neural crest cells, endothelial cells, and cardiomyocytes. In both humans and mice, mutations in components of the Notch signaling pathway result in congenital heart disease characterized by cardiac outflow tract defects. However, the specific cell types in which Notch functions during cardiovascular development remain to be defined. In addition, in vitro studies have provided conflicting data regarding the ability of Notch to promote or inhibit smooth muscle differentiation, while the physiological role for Notch in smooth muscle formation during development remains unclear. In this study, we generated mice in which Notch signaling was specifically inactivated in derivatives of the neural crest. These mice exhibited cardiovascular anomalies, including aortic arch patterning defects, pulmonary artery stenosis, and ventricular septal defects. We show that Notch plays a critical, cell-autonomous role in the differentiation of cardiac neural crest precursors into smooth muscle cells both in vitro and in vivo, and we identify specific Notch targets in neural crest that are implicated in this process. These results provide a molecular and cellular framework for understanding the role of Notch signaling in the etiology of congenital heart disease.

Authors

Frances A. High, Maozhen Zhang, Aaron Proweller, LiLi Tu, Michael S. Parmacek, Warren S. Pear, Jonathan A. Epstein

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Figure 3

DNMAML-GFP is activated specifically in neural crest and somites by Pax3-Cre and does not affect neural crest cell number or migration.

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DNMAML-GFP is activated specifically in neural crest and somites by Pax3...
(A and B) E10.5 Pax3Cre/+ Z/EG control (A) and Pax3Cre/+ DNMAML mutant (B) embryos demonstrating expression of DNMAML-GFP in pharyngeal arches (arrows) and somites (arrowheads). (C and D) Immunostaining for GFP with Hoechst nuclear counterstain on frontal sections through the pharyngeal arches of E10.5 Pax3Cre/+ DNMAML embryos. (C) Low-magnification view showing GFP-positive cells investing the third, fourth, and sixth aortic arch arteries. (D) Higher magnification showing GFP expression specifically in the neural crest–derived mesenchyme of the pharyngeal arch (nc), but not in pharyngeal epithelium (ep) or endothelial cells (ec). (E and F) Immunostaining for GFP on frontal sections through the conotruncus of E11.5 embryos, showing an equivalent number of GFP-positive cells in the conotruncal cushions (arrows) of control (E) and mutant (F) embryos. (G–J) Immunostaining for GFP and α-SMA on frontal sections through the aortic arch arteries of E11.5 embryos. (G and H) Low-magnification view showing equivalent numbers of GFP-positive cells in the pharyngeal region surrounding the 6 major aortic arch arteries (arrows) in control (G) and mutant (H) embryos. (I and J) High-magnification views of the left sixth aortic arch arteries shown in G and H. (K–N) In situ hybridizations for the neural crest cell marker PlexinA2 on frontal sections through the conotruncus (K and L) and the aortic arch arteries (M and N) of E11.5 embryos, showing equivalent expression in control (K and M) and mutant (L and N) embryos. (O and P) GFP expression in the mature aortic arch of control Pax3Cre/+R26RGFP (O) and mutant Pax3Cre/+ DNMAML (P) mice. Scale bars: 100 μm (C, E–H, and K–N), 20 μm (D).