title: Angiogenic morphogenesis driven by dynamic and heterogeneous collective endothelial cell movement.
abstract: Angiogenesis is a complex process, which is accomplished by reiteration of modules such as sprouting, elongation and bifurcation, that configures branching vascular networks. However, details of the individual and collective behaviors of vascular endothelial cells (ECs) during angiogenic morphogenesis remain largely unknown. Herein, we established a time-lapse imaging and computer-assisted analysis system that quantitatively characterizes behaviors in sprouting angiogenesis. Surprisingly, ECs moved backwards and forwards, overtaking each other even at the tip, showing an unknown mode of collective cell movement with dynamic 'cell-mixing'. Mosaic analysis, which enabled us to monitor the behavior of individual cells in a multicellular structure, confirmed the 'cell-mixing' phenomenon of ECs that occurs at the whole-cell level. Furthermore, an in vivo EC-tracking analysis revealed evidence of cell-mixing and overtaking at the tip in developing murine retinal vessels. In parametrical analysis, VEGF enhanced tip cell behavior and directed EC migration at the stalk during branch elongation. These movements were counter-regulated by EC-EC interplay via γ-secretase-dependent Dll4-Notch signaling, and might be promoted by EC-mural cell interplay. Finally, multiple regression analysis showed that these molecule-mediated tip cell behaviors and directed EC migration contributed to effective branch elongation. Taken together, our findings provide new insights into the individual and collective EC movements driving angiogenic morphogenesis. The methodology used for this analysis might serve to bridge the gap in our understanding between individual cell behavior and branching morphogenesis.
authors.affiliation: Department of Physiological Chemistry and Metabolism, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Arima
authors.forename: Koichi
authors.initials: K
authors.lastname: Nishiyama
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ko
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Arima
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hakozaki
authors.forename: Kei
authors.initials: K
authors.lastname: Sugihara
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Koseki
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Uchijima
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Kurihara
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kurihara
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001011:Aorta / Q000166:cytology; D002135:Calcium-Binding Proteins; D002465:Cell Movement / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009024:Morphogenesis / Q000502:physiology*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D051880:Receptors, Notch / Q000235:genetics / Q000378:metabolism; D012171:Retinal Vessels / Q000166:cytology / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D059008:Time-Lapse Imaging
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; C519665:DLL4 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D051880:Receptors, Notch