Laboratory for Vascular Morphogenesis | RIKEN BDR

Laboratory for Vascular Morphogenesis

Team Leader

Li-Kun PhngPh.D.

  • Location:Kobe / Developmental Biology Buildings
  • E-mail:likun.phng[at]riken.jpPlease replace [at] with @.
  • Lab Website

Molecular and mechanical mechanisms regulating blood vessel morphogenesis

Research Summary

The establishment of a network of blood vessels is essential for the development of many tissues and organs. Tissue vascularization frequently occurs through angiogenesis, where new blood vessels arise from pre-existing ones. Angiogenesis encompasses a multitude of cellular processes including collective cell migration, cell elongation, proliferation, anastomosis and lumen formation. While many key molecules and signaling pathways have been identified to regulate blood vessel guidance and arterial-venous differentiation, there is still a poor understanding of how angiogenic signals are relayed to the cell’s machinery to drive changes in endothelial cell morphology and behavior that lead to the final pattern of the vasculature.

My laboratory aims to unravel fundamental mechanisms that regulate endothelial cell behavior and dynamics using the zebrafish as a model system, since it is highly suited for high resolution live imaging, advanced fluorescent microscopy techniques, genetics, cell biology and chemical biology. Previous studies on actin cytoskeleton revealed that specialized F-actin of different dynamics and subcellular localization drive distinct steps of vessel morphogenesis. For example, the transient polymerization of F-actin at the apical membrane controls lumen expansion while a stable pool of F-actin at endothelial cell-cell junctions stabilizes nascent lumens to produce a functional vascular network. In the future, we aim to investigate mechanisms regulating i) endothelial cell shape changes that are necessary for vessel morphogenesis, ii) de novo lumen formation and iii) blood vessel integrity. Our long-term goal is to understand how upstream angiogenic signals and hemodynamic forces regulate endothelial cell cytoskeleton to dictate cell behavior and shape and/or maintain blood vessel architecture.

Sprouting angiogenesis in the zebrafish embryo. Timelapse imaging of an embryo expressing membrane tagged mCherry reveals highly dynamic endothelial cell membrane behaviour during blood vessel development.

Endothelial actin cytoskeleton in zebrafish ISVs (intersegmental vessels) and developing DLAV (dorsal longitudinal anastomotic vessels).

F-actin and apical membrane dynamics during lumen invagination. Local and transient actin polymerization (5', 10') and myosin activity at apical membranes retract inverse blebs and can cause lumen collapse (15'). Remnants of membranes eventually fuse and integrate with the apical membrane of invaginating lumen (25' to 55').

Research Theme

  • How forces regulate endothelial cell shape changes and blood vessel morphogenesis.
  • Mechanisms controlling actomyosin activity in endothelial cells.
  • Molecular regulation of blood vessel lumen formation.

Main Publications List

  • Gebala V, Collins R, Geudens I, et al.
    Blood flow drives lumen formation by inverse membrane blebbing during angiogenesis in vivo.
    Nature Cell Biology 18(4): 443–451 (2016) doi: 10.1038/ncb3320
  • Phng LK, Gebala V, Bentley K, et al.
    Formin-mediated actin polymerization at endothelial junctions is required for vessel lumen formation and stabilization.
    Developmental Cell 32. 123–132 (2015) doi: 10.1016/j.devcel.2014.11.017
  • Phng LK, Stanchi F, and Gerhardt H.
    Filopodia are dispensable for endothelial tip cell guidance.
    Development 140. 4031–4040 (2013) doi: 10.1242/dev.097352
  • Phng LK, Potente M, Leslie J D, et al.
    Nrarp coordinates endothelial Notch and Wnt signaling to control vessel density in angiogenesis.
    Developmental Cell 16. 70–82 (2009) doi: 10.1016/j.devcel.2008.12.009
  • Hellström M, Phng LK, Hofmann J H, et al.
    Dll4 signalling through Notch1 regulates formation of tip cells during angiogenesis.
    Nature 445. 776–770 (2007) doi: 10.1038/nature05571