Sonic hedgehog is required for the assembly and remodeling of branchial arch blood vessels

摘要

Sonic hedgehog (Shh) is a morphogen involved in many developmental processes. Injection of cells (5E1) that produce a Shh blocking antibody, causes an attenuation of the Shh response, and this causes vascular malformations and impaired remodeling characterized by hemorrhages and protrusions of the anterior cardinal vein and outflow tract, delayed fusion of the dorsal aortae, impaired branching of the internal carotid artery and delayed remodeling of the aortic arches. Distribution of smooth muscle cells in the vessel wall is unchanged. In 5E1 injected embryos we also observed impaired assembly of endothelial cells into vascular tubes, particularly in the sixth branchial arch, around the anterior cardinal vein and around dorsal aorta. In 5E1 treated embryos, increased numbers of macrophage-like cells, apoptotic cells and a decreased level of proliferation were observed in head mesenchyme. Together these observations show that Shh signaling is required at multiple stages for proper vessel formation and remodeling.