'In parallel' interconnectivity of the dorsal longitudinal anastomotic vessels requires both VEGF signaling and circulatory flow.
Blood vessels deliver oxygen, nutrients, hormones and immunity factors throughout the body. To perform these vital functions, vascular cords branch, lumenize and interconnect. Yet, little is known about the cellular, molecular and physiological mechanisms that control how circulatory networks form and interconnect. Specifically, how circulatory networks merge by interconnecting 'in parallel' along their boundaries remains unexplored. To examine this process we studied the formation and functional maturation of the plexus that forms between the dorsal longitudinal anastomotic vessels (DLAVs) in the zebrafish. We find that the migration and proliferation of endothelial cells within the DLAVs and their segmental (Se) vessel precursors drives DLAV plexus formation. Remarkably, the presence of Se vessels containing only endothelial cells of the arterial lineage is sufficient for DLAV plexus morphogenesis, suggesting that endothelial cells from the venous lineage make a dispensable or null contribution to this process. The discovery of a circuit that integrates the inputs of circulatory flow and vascular endothelial growth factor (VEGF) signaling to modulate aortic arch angiogenesis, together with the expression of components of this circuit in the trunk vasculature, prompted us to investigate the role of these inputs and their relationship during DLAV plexus formation. We find that circulatory flow and VEGF signaling make additive contributions to DLAV plexus morphogenesis, rather than acting as essential inputs with equivalent contributions as they do during aortic arch angiogenesis. Our observations underscore the existence of context-dependent differences in the integration of physiological stimuli and signaling cascades during vascular development.
Helen L. and Martin S. Kimmel Center for Biology and Medicine at the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016,  USA.
Tomasz
T
Zygmunt
Sean
S
Trzaska
Laura
L
Edelstein
Johnathon
J
Walls
Saathyaki
S
Rajamani
Nicholas
N
Gale
Laura
L
Daroles
Craig
C
Ramírez
Florian
F
Ulrich
Jesús
J
Torres-Vázquez
D000818:Animals; D001163:Arteriovenous Anastomosis / Q000166:cytology / Q000196:embryology*; D002465:Cell Movement; D049109:Cell Proliferation; D042783:Endothelial Cells / Q000502:physiology; D051379:Mice; D009024:Morphogenesis; D018919:Neovascularization, Physiologic; D060726:Torso / Q000098:blood supply / Q000196:embryology; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism* / Q000502:physiology; D015027:Zebrafish
D042461:Vascular Endothelial Growth Factor A