Neural crest–derived SEMA3C activates endothelial NRP1 for cardiac outflow tract septation
Alice Plein, Amélie Calmont, Alessandro Fantin, Laura Denti, Naomi A. Anderson, Peter J. Scambler, Christiana Ruhrberg
Alice Plein, Amélie Calmont, Alessandro Fantin, Laura Denti, Naomi A. Anderson, Peter J. Scambler, Christiana Ruhrberg
View: Text | PDF
Research Article Vascular biology

Neural crest–derived SEMA3C activates endothelial NRP1 for cardiac outflow tract septation

Abstract

In mammals, the outflow tract (OFT) of the developing heart septates into the base of the pulmonary artery and aorta to guide deoxygenated right ventricular blood into the lungs and oxygenated left ventricular blood into the systemic circulation. Accordingly, defective OFT septation is a life-threatening condition that can occur in both syndromic and nonsyndromic congenital heart disease. Even though studies of genetic mouse models have previously revealed a requirement for VEGF-A, the class 3 semaphorin SEMA3C, and their shared receptor neuropilin 1 (NRP1) in OFT development, the precise mechanism by which these proteins orchestrate OFT septation is not yet understood. Here, we have analyzed a complementary set of ligand-specific and tissue-specific mouse mutants to show that neural crest–derived SEMA3C activates NRP1 in the OFT endothelium. Explant assays combined with gene-expression studies and lineage tracing further demonstrated that this signaling pathway promotes an endothelial-to-mesenchymal transition that supplies cells to the endocardial cushions and repositions cardiac neural crest cells (NCCs) within the OFT, 2 processes that are essential for septal bridge formation. These findings elucidate a mechanism by which NCCs cooperate with endothelial cells in the developing OFT to enable the postnatal separation of the pulmonary and systemic circulation.

Authors

Alice Plein, Amélie Calmont, Alessandro Fantin, Laura Denti, Naomi A. Anderson, Peter J. Scambler, Christiana Ruhrberg

×

Figure 3

Endothelial-, not NCC-derived NRP1 enables OFT septation.

Options: View larger image (or click on image) Download as PowerPoint
Endothelial-, not NCC-derived NRP1 enables OFT septation. (A) Serial sec...
(A) Serial sections of Wnt1-Cre RosaYfp and Tie2-Cre RosaYfp E12.5 OFTs at corresponding distal, medial, and proximal levels, labeled for YFP and DAPI. Angles and solid arrows highlight NCC contribution to the valves and septal bridge, respectively; solid arrowheads indicate endothelium of the aorta and pulmonary artery; and curved arrows indicate cells undergoing endoMT. Note the overlap of NCC position and endoMT in the proximal OFT. Shaded areas are shown in higher magnification on the right, with open and solid arrowheads indicating absence and presence of endothelial targeting, respectively. (B) Serial sections of Wnt1-Cre Nrp1fl/fl (n = 4), Wnt1-Cre Nrp1fl/fl Nrp2–/– (n = 3), Tie2-Cre Nrp1fl/fl (n = 6), and control (n = 7) E12.5 OFTs of the indicated genotypes, immunolabeled for PECAM and SMA. Solid arrowheads indicate endothelium of the aorta and pulmonary artery; solid arrows indicate septal bridge myocardialization; and open arrows indicate absence of septal bridge formation. Wavy arrows highlight migrating SMA-positive cells, while the angle highlights stalled SMA-positive cells. Dotted lines indicate the axis of OFT septation, and the open arrowhead indicates an atypical association between endothelium and myocardium. Scale bars: 100 μm (A); 200 μm (B).