title: Notochord-derived BMP antagonists inhibit endothelial cell generation and network formation.
abstract: Embryonic blood vessel formation is initially mediated through the sequential differentiation, migration, and assembly of endothelial cells (ECs). While many molecular signals that promote vascular development have been identified, little is known about suppressors of this process. In higher vertebrates, including birds and mammals, the vascular network forms throughout the embryonic disk with the exception of a region along the midline. We have previously shown that the notochord is responsible for the generation and maintenance of the avascular midline and that BMP antagonists expressed by this embryonic tissue, including Noggin and Chordin, can mimic this inhibitory role. Here we report that the notochord suppresses the generation of ECs from the mesoderm both in vivo and in vitro. We also report that the notochord diminishes the ability of mature ECs to organize into a primitive plexus. Furthermore, Noggin mimics notochord-based inhibition by preventing mesodermal EC generation and mature EC network formation. These findings suggest that the mesoderm surrounding the midline is competent to give rise to ECs and to form blood vessels, but that notochord derived-BMP antagonists suppress EC differentiation and maturation processes leading to inhibition of midline vessel formation.
authors.affiliation: Cardiovascular Research Institute, University of California San Francisco, 4(th) Street, Box2711, San Francisco, CA 94158-2324, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Bressan
authors.forename: Patricia
authors.initials: P
authors.lastname: Davis
authors.forename: John
authors.initials: J
authors.lastname: Timmer
authors.forename: Doris
authors.initials: D
authors.lastname: Herzlinger
authors.forename: Takashi
authors.initials: T
authors.lastname: Mikawa
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology; D019485:Bone Morphogenetic Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D002642:Chick Embryo; D042783:Endothelial Cells / Q000166:cytology* / Q000502:physiology; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism; D009672:Notochord / Q000502:physiology*; D011784:Quail; D000099176:Noggin Protein
chemical_list: D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D000099176:Noggin Protein; C054234:chordin